The author hereby grants to MIT permission to reproduce and to distribute publicly paper and electronic copies of this thesis document in whole or in part
Signature of the Author___________________________________________________________
Department of Civil and Environmental Engineering May 9, 2003
Oral Buyukozturk Chairman, Departmental Committee on Graduate Studies
Policy for Development of Water and Wastewater Infrastructure in Paraty, Brazil
by
Eun Chu You
Submitted to the Department of Civil and Environmental Engineering on May 15, 2003 in partial fulfillment of the requirements for the degree of
Master of Engineering in Civil and Environmental Engineering Abstract The purpose of this thesis is to identify and describe Paraty’s current problems related to existing water and sanitation systems, and to recommend practical improvements for the mitigation of these problems. Water quality analysis of Paraty’s potable water and surrounding surface waters is central to the evaluation of public health risks, associated with the consumption of ineffectively treated water and exposure to unsanitary disposal of human wastes. Additionally, the study of diarrhea incidence in the City is integral to the measurement of direct health consequences resulting from inadequate water and sanitation.
In addition to poor public health, the consequences of the City’s inadequate water and sanitation include: polluted surface waters; damaged aesthetics; loss of amenities; depreciated commercial and intrinsic value of the environment; and deferred nomination process for UNESCO World Heritage Site.
The construction of wastewater collection infrastructure and treatment plant, and new drinking water treatment plant, is recommended for the City. An increase in water and sewage tariff is suggested as a means of recovering the costs incurred by new water and sanitation improvements. Integrating a cost analysis and a willingness to pay analysis, it was found that the costs could be recovered if water and sewage tariff is priced effectively, based on the distribution of household income and willingness to pay. Thesis Supervisor: Dr. Donald Harleman Title: Ford Professor Emeritus of Civil and Environmental Engineering
3
Acknowledgements I would like to thank the following individuals: Dr. Donald Harleman for his unreserved support. I would like to thank him especially for the weekly meetings, which have been invaluable for the completion of the Brazil Project and this thesis. Frederic Chagnon for all his help, which always came when help was needed most. Mr. Ricardo Tsukamoto for all his help during and after my stay in Paraty. The Tsukamoto family for providing the cutest laboratory, and a wonderful Sunday at the beach. Ms. Wilsa Mary S. Barreto, for generously sharing her work. My teammates Claire Kfouri, Nancy Choi, and Hyo Jin Kweon, for many unforgettable memories in Paraty and M.Eng room. The CEEKA members for their constant interest and encouragements. I would to thank the CEEKA members especially for making me feel at home and giving me many wonderful memories at MIT. My sisters Lisa and Sunny You for being the best sisters and friends anyone can wish for. I would like to also thank my brother Paul and his wife Myung Rye You. My parents Yong Chan and Soon Duk You for their unfailing love.
Table 4.5. Total capital cost and O&M cost for drinking water treatment plant ...........................69
Table 4.6. Equivalent uniform annual cost and break-even tariff for water and sewage ..............70
Table 4.7. Benefit/cost ratio for water and sewage tariff = R$1.60/m^3.......................................71
Table 4.8. Water and sewage tariff adjusted according to income distribution.............................75
Table 4.9. Total capital cost and O&M cost for water and sanitation improvement projects .......76
9
CHAPTER 1 - INTRODUCTION TO WATER AND SANITATION
The provision of safe drinking water and the proper treatment and disposal of human waste can
achieve large gains in human health, and environmental quality, and hence provides substantial
economic returns. Therefore naturally, the provision of adequate drinking water supply and
sanitation ranks at the top of priority environmental challenges in Paraty, Brazil, as well as in
many parts of the developing world. In this report, drinking water supply refers to a system or
service of water collection, drinking water treatment, and water distribution for human
consumption. Sanitation is defined as the services or systems of collection, transportation,
treatment, and sanitary disposal of wastewater, excreta, or other waste.
1.1. Health Consideration
Many studies report that unreliable drinking water quality and supply and the lack of wastewater
treatment has a significant impact on health. The use of polluted waters for drinking and bathing
causes infectious diseases that kill millions and sicken more than a billion people each year
(World Bank, 1992). Thousands of outbreaks of waterborne diseases are caused by the
consumption of untreated or improperly treated drinking water (Ford and Colwell, qtd. in
Payment and Hunter, 2001).
Water and sanitation-related diseases are transmitted through many pathways, and can be
classified into four categories: (i) waterborne diseases, caused by the ingestion of water
contaminated by human or animal feces or urine containing pathogenic bacteria or viruses; (ii)
water-washed diseases, caused by poor personal hygiene; (iii) water-based diseases, caused by
parasites found in intermediate organisms living in water; and (iv) water-related diseases,
transmitted by insect vectors that breed in water (Eisenberg et al., 2001). Examples of these
diseases are listed in Table 1.1.
10
Category Disease Waterborne diseases Cholera, typhoid, amoebic and bacillary dysentery, and other diarrheal
diseases Water-washed diseases Scabies, trachoma and flea-, lice-, and tick-borne diseases, in addition to
the majority of waterborne diseases, which are also water-washed Water-based diseases Dracunculiasis, schistosomiasis, and some other helminths Water-related diseases Dengue, filariasis, malaria, onchocerciasis, trypanosomiasis, and yellow
fever Table 1.1. Examples of water-related diseases (Bradley, qtd. in Eisenberg, 2000)
The direct health consequence of poor water supply and sanitation is huge. According to the
World Health Organization (WHO), approximately one child dies every eight seconds from a
water-related disease, and more than 5 million people died each year from illnesses linked to
unsafe drinking water or inadequate sanitation (Anon, qtd. in Payment and Hunter, 2001).
“Unsafe water is implicated in many cases of diarrheal diseases, which, as a group, kill more
than 3 million people, mostly children, and cause about 900 million episodes of illness each year.
At any one time more than 900 million people are afflicted with roundworm infection and 200
million with schistosomiasis. Many of these conditions have large indirect health effects –
frequent diarrhea, for instance, can leave a child vulnerable to illness and death from other
causes” (World Bank, 1992).
Children, the poor, and travelers are most at risk of water and sanitation-related diseases, due to
undeveloped or degraded immunity for disease-causing environmental pathogens. Children
under 5 years of age are the most vulnerable population, because they are “in a dynamic state of
growth” (WHO, “Children”). Also, children are “more exposed to unhealthy conditions and to
dangerous substances because they live their lives closer to the ground and, especially in the
early years, they are frequently exposed through hand-to-mouth activities” (WHO, “Children”).
People from low-income areas are more likely to suffer disease due to increased exposure to
pathogens from poor living conditions, and are likely to suffer more severely, once affected by
disease, “because of inadequate health-care and social support systems, and from poorer general
health due to malnutrition” (Eisenberg et al., 2001). Therefore, not surprisingly, poor children
suffer the most, and approximately “one in five children in the poorest parts of the world will not
live to their fifth birthday, mainly because of environment-related diseases” (WHO, “Children”).
For the third group of vulnerable population, travelers, the risk of infection is higher because
11
they are exposed to new environmental pathogens, to which they do not have acquired immunity
due to prior exposure. Most waterborne pathogens have acquired immunity, the protection
conferred to a host after exposure to the agent of disease, that is partial and temporary (Eisenberg
et al., 2001).
The reduction in water-related illnesses with improvements in water and sanitation is large.
“WHO suggest that if sustainable safe drinking water and sanitation services were provided to
all, each year there would be 200 million fewer diarrheal episodes, 2.1 million fewer deaths
caused by diarrhea, 76,000 fewer dracunculiasis, 150 million fewer schistosomiasis cases and 75
million fewer trachoma cases” (Payment and Hunter, 2001). The effects of improved water and
sanitation on the occurrence of related illnesses, studied by the U.S. Agency for International
Development (USAID), is summarized in Table 1.2, and the effects on the morbidity from
diarrhea, studied by WHO, is summarized in Table 1.3 below. The WHO analysis suggests that
the effects of making several kinds of improvements at the same time are roughly additive (Esrey
at al., qtd. in World Bank, 1992).
Disease Millions of people affected by illness Median reduction attributable to improvement (%)
Table 1.2. Effects of improved water and sanitation on water and sanitation-related illnesses (Esrey et al., qtd. in The World Bank, 1992)
Type of improvement Median reduction in morbidity (%) Quality of water 16 Availability of water 25 Quality and availability of water 37 Disposal of excreta 22
Table 1.3. Effects of improved water and sanitation on morbidity from diarrhea (Esrey et al., qtd. in The World Bank, 1992)
Some epidemiological evidence suggests that improvements in sanitation are at least as effective
in preventing disease as improved water supply (UNICEF et al., 2000). The improvement in
12
wastewater treatment and disposal interrupts the transmission of much fecal-oral disease at its
most important source by preventing human fecal contamination of water and soil.
Water and sanitation-related diseases are prevalent in Brazil, where the delivery of drinking
water and sanitation services falls far short of the goal of universal coverage. In Brazil,
approximately 75% of the total population is served with domestic water connection, and 48% is
served with a connection to public sewer system. Among the urban population, which accounts
for 78% of the Brazil’s total population of 162 million, 91% is served with domestic water
connection, and 59% is served with connection to public sewer system. Among the rural
population, 20% has domestic water connection, and mere 6% has connection to public sewer
system. More alarmingly, only 10% of the total volume of sewage collected from the sewerage
systems receives treatment (CEPIS, 2000).
The prevalence of water and sanitation-related diseases, which corresponds to low water and
sanitation service coverage, in Brazil is considerable. As much as 32% of all hospital admissions
in 1990, were due to diseases related to inadequate sanitation, according to a 1995 report from
the Ministry of Planning and Budget of Brazil titled ‘Assessment of the Sanitation Sector:
Economic and Financial Study’ (Csillag and Zorzetto, 2000). This report revealed that as many
as 4.5 million hospital admissions, registered by the Ministry of Health from 1987 to 1992, were
caused by sanitation-related diseases. The main group of diseases, labeled “poorly defined
enteric infection,” caused 92% of the cases, and the remaining 8% comprised what are labeled as
“other specific enteric infections,” as well as typhoid fever, shingellosis, schistosomiasis, and
amebiasis. Furthermore, this report remarked that infant mortality is two times higher in
households with inadequate sanitation than in households with adequate sanitation, revealing a
strong correlation between limited service coverage of water and sanitation and poor public
health.
1.2 Environmental Quality Consideration
In addition to losses in human health, there are many costs related to environmental degradation,
such as losses in productivity, amenity, and the intrinsic value of the environment. The
13
productivity includes both the human productivity that can be lowered by impaired health, and
the productivity of many resources, used directly or indirectly by people, that can decline with
damage imposed by those uses (World Bank, 1992). Amenity is “a term that describes the many
other ways in which people benefit from the existence of an unspoiled environment” (World
Bank, 1992). The “intrinsic” value of the environment is separate from its value to human
beings, that can only estimated under the notion of amenity values.
The quality of many surface water bodies – such as rivers, streams, and beach waters – have
economic values, as fisheries and/or recreational waters, aesthetic value that can add to quality of
life, and the intrinsic value, all of which depend on the state of water and sanitation systems.
1.3 Economic Consideration
Water is an economic good, with many competing uses, that can be a driving force for social and
economic development. In countries where tourism is an important contributor of foreign
exchange and employment, the preservation of attractive environment, through proper
management of sanitation infrastructure and wastewater treatment facilities, becomes critical for
the development of the industry. Polluted environment, such as a beach contaminated with
human wastes, and its associated health risks for tourists and local population can easily pose a
threat for the development and survival of the tourism industry (San Martin, 2002).
Tourism
Tourism contributes significantly to the economies of developing countries by achieving “three
high-priority goals of developing countries: the generation of income, employment, and foreign
exchange earnings” (San Martin, 2002). Tourism, classified as exports, accounts for a
significant portion of the GDP earnings in the Latin American and Caribbean countries, although
this portion is not fully reflected in the domestic income and product accounts of most countries.
In Brazil, tourism accounts for approximately 4% of total exports (World Bank, qtd. in San
Martin, 2002). In 1997, the Brazilian exports totaled US$ 53 billion (BIT, n.d.). Thus, tourism
accounted for approximately US$2 billion of exports in 1997.
14
Tourism, which does not require sophisticated technology or much skilled training, is a great
generator of employment and income. “[In] hotels, which account for about 75 percent of
tourism employment (distribution, transport, finance and insurance, and entertainment make up
the other 25 percent), [e]very room in a three- or four-star hotel generates one job, for five-star
hotels, each room creates 1.3 jobs” (San Martin, 2002). “Even before the 1990s, one job
generated by a hotel generated one more job elsewhere in the tourism trade and two in the rest of
the economy; thus one job generated an estimated three others” (IDB, qtd. in San Martin, 2002).
“It is estimated that in the Latin American and the Caribbean five-star hotels can generate
US$5.4 for each dollar spent in their operation. The figure for three- and four-star hotels
averages US$4.2” (San Martin, 2002).
1.4. Social Consideration
In addition to the economic contributions, there are important social contributions associated
with water and sanitation, the most significant of which, aside health, is poverty alleviation.
Poverty Alleviation
Water and sanitation infrastructure can promote poverty alleviation by: (i) stimulating economic
growth; (ii) converging the poor and rich regions within a country; (iii) increasing agricultural
productivity through by improving irrigation; and (iv) improving the health and productivity. “It
has been estimated that in Latin America, a 1 percent growth in per capita income reduces the
share of the people living in poverty by half a percentage point” suggesting that “any
contribution of infrastructure to growth will therefore have a poverty alleviation effect” (San
Martin, 2002). “In Argentina and Brazil, recent studies show that lack of access to sanitation and
to roads over the last 20 years have been important impediments to convergence [between the
poor and the rich regions]” (San Martin, 2002). “With large percentage of the population
employed in agriculture in the low-income economies of Latin American countries, investments
in irrigation and agriculture more generally and improvements in water management, in
particular, can have substantial impacts on rural poverty alleviation” (San Martin, 2002).
“Extending coverage rates for water supply and sanitation will affect the living conditions of the
poor via better health, and increased potential labor productivity; through considerable cash
15
savings (since their supplies must often be bought extensively, from water trucks, bottled water,
etc.); and through reduced time use in bringing the water to the household” (San Martin, 2002).
1.5. Institutional Framework in Brazil
Much of the water and sanitation sector in Brazil currently follows the PLANASA (Plano
Nacional de Saneamento) model, which is responsible for 80% of water supply and 32% of
sewage services for the urban population. Created in 1971, with the goals of improving water
supply and sanitation services, PLANASA required each State in Brazil to create its own State-
owned public company, from which the municipalities were able to contract services for water
and sanitation. The municipalities had the choice of awarding concession contracts to the public
company or establishing their own public services, a right granted by the Brazilian Constitution.
However, the Federal National Bank of Housing (Banco Nacional de Habitao), under the
Ministry of the Interior, did not finance water and sanitation works unless the municipality had
joined PLANASA. Although the Federal National Bank of Housing, and PLANASA were
abolished in 1986, the PLANASA model remains operational as the backbone of water and
sanitation sector in Brazil (US Dept. of Commerce, 1999).
As the concession period from the municipalities to the State companies reaches their end,
changes are actively sought. The State companies had shown inadequate performance and low
productivity in many cases and had left many consumers, who often viewed their services as
unreliable, discontent with their services. The State companies had some typical and common
problems, which the World Bank classified into four groups: (i) technical and operational, (ii)
commercial and financial, (iii) human and institutional, and (iv) environmental problems. The
municipalities are looking for new models or for a new role of the State in providing public
services, with the emphasis on decentralization and privatization, as it has occurred in other parts
of the world. The service contracts (for pumping stations, sewage treatment plants, metering and
reading, for example), and the discussion of private sector participation are becoming more
common (US Dept. of Commerce, 1999).
16
CHAPTER 2 - INTRODUCTION TO PARATY, BRAZIL
The area of focus for the water and sanitation studies in this report is the City of Paraty, located
in the State of Rio de Janeiro, Brazil. Paraty is a historical city, with much natural and cultural
charm, that has a potential to grow as a tourist city. However, doubtful drinking water quality
and polluted rivers and beach water, which are associated with lack of wastewater treatment,
could very well threaten the health of tourists and local population, and hinder the development
of the tourism industry. Therefore, a careful study of the City’s current state of water supply and
sanitation, the extent of environmental degradation, and appropriate response measures are to be
studied for the City of Paraty in this report.
2.1 Location, Area, Climate, and Population
The City of Paraty is located within the Municipality of Paraty, which is located in the south
coast of the State of Rio de Janeiro, Brazil (See Figure 2.1 through 2.3). The Municipality of
Paraty covers an area of 930 km2, with the average elevation of 5 meters (Prefeitura,
“Patrimony” 3). Embracing the Bay of Ilha Grande (Baia da Ilha Grande), Paraty has the mild
climate that is hot in the afternoon most of the year, and receives more than 1.5 m of rainfall
each year (Canaldotempo.com).
Figure 2.1. Location of Municipality of Paraty in the State of Rio de Janeiro, Brazil
17
The Municipality of Paraty has a population of 30,000 (Census 2000), approximately 15,000 of
which are concentrated in the urban area, in and near the City of Paraty. The other 15,000 are
dispersed in smaller rural communities around the Municipality (See Figure 2.2).
Figure 2.2. Municipality of Paraty (Not to Scale)
2.2. City of Paraty
The City of Paraty, which has the highest population density in the Municipality, has two rivers,
Pereque River (Rio Pereque-Acu) and Matheus River (Rio Matheus-Nunez), running through it
and discharging into the Paraty Bay (Baia Paraty) (See Figure 2.3). Matheus River, in the South,
forms the southern boundary of the City, and the northern end of Jabaquara Beach (Praia
Jabaquara) forms the northern boundary.
18
The City can be subdivided into five sections: (1) Historical Center; (2) the Old City; (3)
Manguera; (4) Ilha das Cobras; and (5) Jabaquara (See Figure 2.3.b). Paraty’s Historical Center,
which preserves the authentic colonial architecture, from the 17th century when Paraty was a
major staging post for Brazilian gold passing from Minas Gerais to Portugal, is a national
monument, considered by UNESCO (United Nations Educational, Scientific and Cultural
Organization) to be one of the most important surviving examples of colonial architecture in the
world. The streets in the historical center are paved with irregular stones, which form a canal
that drains off storm water and allows for the sea to enter and wash the streets at full moon and
high tides. Manguera and Ilha das Cobras are the poorer areas of the City. The Old City and
Jabaquara consists mainly of inns and other accommodations for tourists, and are generally
wealthier areas.
Figure 2.3.a. City of Paraty (Not to Scale) Figure 2.3.b. City of Paraty (Not to Scale)1
The City has a total population of approximately 15,000, which increases manifold during
summer due to tourism. The increases in population during summer is greatest for the Historical
Center, a great tourist attraction, and for Old City and Jabaquara, which are mainly summer
1 1) Historical Center; 2) Old City; 3) Mangueira; 4) Ilha das Cobras; and 5) Jabaquara
19
resort areas. In contrast, population increase is not expected for Mangueira and Ilha das Cobras
areas, which are mainly residential areas for the local population.
2.3. Tourism Industry
The tourism industry in Paraty is active and strong, and is considered one of the largest
contributors to the City and Municipality’s economy, next to fishing, trade, and craft (Prefeitura,
“Patrimony,” 2003). Reflecting the City’s thriving tourism industry, are many lodgings and
hotels, pubs and restaurants, stores and boutiques, and travel agencies located in the City.
Besides the Historical Center, there are many more tourist attractions, some of which include:
islands; waterfalls; beaches; natural parks of preservation; museums; historical monuments;
military forts; and folkloric parties (Prefeitura, “Patrimony,” 2003). The City’s location, situated
advantageously between the two largest cities in Brazil, Rio de Janeiro and Sao Paulo, helps the
tourism industry by allowing tourists to travel conveniently through either of the two cities. Sao
Paulo and Rio de Janeiro have the two busiest airports in Brazil, and there were approximately
2.8 million international arrivals in Sao Paulo Airport, and 1 million in Rio de Janeiro Airport, in
2001, according to a poll taken by the Brazilian Tourist Office.
2.4. Candidacy for UNESCO World Heritage Site
The well-preserved 17th century colonial architecture in Paraty’s Historical Center is the
Brazilian national historic monument, and a candidate for UNESCO World Heritage Site. The
World Heritage List, a direct result of the adoption of the Convention Concerning the Protection
of the World Cultural and National Heritage by UNESCO in 1972, authenticates, in an area or
monument, the existence of heritage that belongs to and is important to humanity. To be
included in the World Heritage List, sites must satisfy severe selection criteria, following an
extensive nominating procedure. A cultural criteria for the World Heritage Site follows: “works
of man or the combined works of nature and of man, and areas including archaeological sites
which are of outstanding universal value from the historical, aesthetic, ethnological or
anthropological points of view” (UNESCO, 1997).
20
Paraty, which has initiated the nomination process for the UNESCO World Heritage Site, is in
the stage of planning the improvements in water and sanitation, which are a few of the
requirements specified by ICOMOS (the International Council on Monuments and Sites), one
UNESCO’s two technical advisory bodies. The current, non-existing, system of wastewater
treatment and disposal in Paraty was identified as unsatisfactory, and a system that complies with
domestic and international standards is required, in order for Paraty to qualify as a candidate for
World Heritage Site.
21
CHAPTER 3 – PRESENT CONDITION OF WATER AND SANITATION
3.1. Institutional Framework in Paraty
The water and wastewater sector in the Municipality of Paraty is in a state of instability and
faced with an uncertain future. Since the concession period, from the Municipality to CEDAE
(the Rio de Janeiro State-owned water and sewage company), expired approximately 6 years
ago, the Municipality has neither renewed its contract with CEDAE nor completed a full transfer
of the control of its water and sanitation systems. While the Municipality remains undecided in
its approach toward its repossessed water and sanitation systems, CEDAE continues to provide
services without having established a new concession agreement with the Municipality. In the
past, CEDAE has made apparent efforts to renew its concession with the Municipality, by
making propositions such as: (i) spending R$200,000 for fixing and making operational a
partially constructed and abandoned drinking water treatment plant; and (ii) spending R$10
million for the operation and maintenance of potable water treatment and distribution (Lemos
Padua, 2003). However no agreement has been reached.
The extent of Municipality’s participation in its own water and sanitation sector depends largely
on the interests of the individuals in political power. During the seat of previous mayor, Dede,
the Municipality had constructed new water supply pipeline, begun the construction of a potable
water treatment plant, and measured domestic water consumption using water meters. However,
with the election of new mayor in 2000, many of these projects were abandoned while new
projects were devised and undertaken. For example, the Municipality had abandoned the
construction of the treatment plant, discontinued the reading of water meters, set the tariffs for
water and sanitation according to property size, and informally entrusted CEDAE with much of
the water and sanitation services since 2001 (Reis, 2003).
3.2. Services Coverage
Paraty has a coverage of water supply and sanitation services that is lower than the national
average, which is itself far below the desired universal coverage. According to a report prepared
22
by the Municipality of Paraty in 2002, 60% of the total population in Paraty is supplied with
public water that is disinfected with chlorine, and 12% is provided with sewage collection, that
discharges, untreated, directly to surrounding surface water bodies (Prefeitura, “Laudo,” 2002).
This figure is lower than the nationwide average of 75% domestic water connection, and 48%
connection to public sewer system.
The disparity is even greater when the coverage in Paraty is compared with the coverage in Rio
de Janeiro, one of nation’s largest cities, that is also near Paraty. In Rio de Janeiro, where more
than 99% of the population is in the urban area, 90% of the urban population has domestic water
supply connection and 84% has connection to public sewer system (CEPIS, 2000). To compare
more equitably, it is important to note that approximately 100% of the urban population in Paraty
receives water that is disinfected with chlorine, and 0% of the wastewater collected is treated
before discharge. In contrast, 77% of the total population in Rio de Janeiro receives effectively
disinfected water through the distribution network; and 41% of the total wastewater produced in
Rio de Janeiro is treated (CEPIS, 2000).
3.3. Existing Potable Water Supply System
Paraty, which receives more than 1.5 m of rainfall each year, is well endowed with an abundant
supply of drinking water sources at the mountains. These drinking water sources, most of which
are surface waters in the form of streams or rivers, have pristine water quality most of the time.
Unfortunately, however, surface waters are easily contaminated with increased amounts of
particulate matter in the water after rainstorms, due to erosion of sediments caused by rapid
currents. In addition, surface waters are contaminated by the runoffs from upstream areas; so the
presence of farms upstream or nearby can easily pollute the waters with fertilizers and animal
feces. Therefore, the potable water, with surface waters as its source, has highly variable water
quality, and requires the minimum treatment of filtration and disinfection.
Despite these problems of frequent rainstorms and farms located near and upstream of the water
intake points, the Municipality of Paraty disinfects only two of its many water sources, those that
23
serve the urban population in the City of Paraty. The disinfection is performed by the addition of
chlorine and without filtration or any other form of pretreatment.
In the entire Municipality of Paraty, there are two other systems of potable water that receive
treatment, and they are provided by private sectors for private developments. The first system,
Condominio Laranjeiras, serves approximately 500 households in Laranjeiras and Vila Oratorio,
and the other system, Vila Residencial da Eletronuclear, serves approximately 680 households in
private developments in the Mambucaba area (Prefeitura, “Vigilancia,” 2001). Both systems are
described as conventional treatment with disinfection. The rest of the rural communities in
Paraty consume water that is brought from various surface water sources in the mountains, and
some groundwater sources.
Potable Water Infrastructure
The City of Paraty is supplied with disinfected water that is brought from two surface water
sources, called Pedra Branca and Caboclo. The intake points of Pedra Branca and Caboclo are
located in the mountains, approximately 7 km and 4 km west of the City, respectively. Pedra
Branca withdraws water from Pereque River (Rio Pereque-Acu), which also flows through the
City of Paraty further downstream, immediately before discharging into Paraty Bay (Baia
Paraty).
Pedra Branca and Caboclo operate in a complementary system, in supplying water to the City of
Paraty (See Figure 3.1). The water from Pedra Branca is disinfected with chlorine gas at the
source and transported to a reservoir located next to the City of Paraty, where it is combined with
the water from Caboclo that has not been chlorinated. The water is disinfected with chlorine gas
at the reservoir, before it is distributed to the City of Paraty. The water is not filtered before
disinfection. The complementary water supply system, Pedra Branca and Caboclo combined,
supplies water to approximately 3,850 households in the City of Paraty as well as the rural areas
near the intake points. The average water consumption in the City is approximately 180 L of
water per capita per day, according to a report prepared by the Municipal City Hall of Paraty
(Prefeitura, “Vigilancia,” 2001).
24
Figure 3.1. Schematic diagram of water supply system for the City of Paraty
Pedra Branca Intake
The water intake system at Pedra Branca, which withdraws water from Pereque River, consists
of a concrete dam (W = 23 m, H = 2.1 m), a grit box (L = 6.4 m, W = 1.2 m, H = 2.9 m), also
constructed in concrete, and 48 meters of 400 mm intake pipe that connects these two structures.
The grit box, located below the dam, captures sand that is mixed with water, and the collected
sand is removed from the grit box periodically. Water is disinfected with chlorine gas after it
leaves the grit box, before it is taken to the city’s reservoir by two 200 mm pipes. One of the two
200 mm pipes is iron pipe, constructed by CEDAE in 1975, and it stretches 6,000 meters from
the grit chamber to the City’s reservoir. However, the other 200 mm pipe, which is PVC pipe,
extends only 3,000 meters and does not connect to the reservoir, although it was built by the City
to serve as a duplicate of the iron pipe (Prefeitura, “Laudo,” 2002).
Caboclo Intake
The water intake system at Caboclo consists of a concrete dam (W=5.3 m, H=1.1 m), a narrow
concrete channel (L=17.9 m, W=1.2 m, H=0.8 m), and two stabilizing basins also in concrete,
which act as grit boxes. A 150 mm iron pipe stretches 3,000 meters from Caboclo to Jabaquara,
and a 150 mm PVC pipe transports water from Caboclo to the City’s reservoir. The Caboclo
intake system was constructed by the City of Paraty in 1999 (Prefeitura, “Laudo,” 2002).
Reservo
Pedra Branc
Jabaquar
City of Paraty
Chlorination
Chlorination
Cabocl
25
Reservoir
The City’s reservoir, which receives chlorinated water from Pedra Branca and raw water from
Caboclo, is located on a small hill, near the City of Paraty. The reservoir, built by the CEDAE in
1975, consists of two adjacent tanks, each with dimensions of L=16 m, W=11 m, and H=3.2 m.
The total capacity of the reservoir is 106 liters, with the hydraulic residence time of
approximately 9 hours. The hydraulic residence time is estimated by assuming that the flow into
and out of the reservoir is equal to the daily consumption of 0.7 million gallons, by the City of
Paraty.
System of Disinfection by Chlorination
The disinfection of water by chlorination, at Pedra Branca and at the City’s Reservoir, is
performed in a crude, trial-and-error method. The City has no water meter at the reservoir to
measure the flow into and out of the reservoir, which varies daily, and thus, no reliable method to
determine the required chlorine dosage. In general, an administrator of chlorination adds
approximately 200 grams of chlorine gas to the reservoir water each day, after adding an
unknown amount of chlorine at the Pedra Branca intake (de Sigueira Baffo, 2003). The
administrator adds as much as 400 grams of chlorine gas at the reservoir each day if no chlorine
is added at Pedra Branca. The administrator does not measure chlorine demand in the reservoir
water, but measures residual chlorine concentration in the City’s tap water using a swimming
pool kit, to adjust the subsequent day’s chlorine dosage using this measurement. For example, if
the residual chlorine concentration in the City’s tap water were below the target concentration of
0.5 mg/l today, the administrator would increase the chlorine dosage tomorrow. The time lag of
1 day between the measurement and adjustment makes correct chlorine dosage difficult.
The residual chlorine in the City’s tap water, measured by the administrator using a swimming
pool kit, is approximately 2.5 mg/l on average. However, the residual chlorine concentration
varies widely when it is measured with a more precise method. The residual chlorine measured
with Hach standard methods, ranges from 0.0 mg/l to 1.5 mg/l. The recommended concentration
of residual chlorine in drinking water is 0.5 mg/l for effective disinfection. The residual chlorine
concentration in water is discussed further in Section 3.4.
26
3.4. Problems with Potable Water Supply
The potable water supply system for the City of Paraty has a number of problems that must be
addressed. The most important problems are: (i) shortage of water supply in the summer; (ii)
ineffective disinfection; (iii) inadequate protection of water sources; and (iv) substandard water
quality.
Supply Shortage
The City experiences water shortage during summer time, when the City’s population increases
dramatically with tourists. The problem with water shortage has been prevalent in the past,
although the situation has improved in the recent years. Despite the abundant amount of source
water, which increases in the summer with frequent rainstorms, the supply often does not meet
increased demand. It is estimated that the City’s population increases manifold in the summer,
as much as 3 to 10 times according to some local people. In the past, water shortage in summer
was very frequent and some lasted as long as three days (Lemos Padua, 2003). In the more
recent years, since the construction of duplicate water supply pipelines, from 1997 to 2000, the
water shortage has become less frequent, but has not been eliminated.
Water shortages impose much inconvenience and distress to anyone who experience it.
Therefore, water shortages, especially those that last long, have the capacity to generate
enormous public discontent, and can affect the local people and tourists alike.
Ineffective Disinfection
The disinfection of City’s potable water is as unreliable as the method of chlorine addition is
imprecise. Due to inaccurate chlorine dosage, the drinking water is distributed with variable
amounts of residual chlorine. The residual chlorine in the City’s tap water is sometimes
undetectable, according to laboratory measurements.
Ineffective disinfection is problematic, mainly because tests of fecal coliform bacteria show that
the City’s water source is contaminated with fecal matter. Pathogenic fecal coliform bacteria, E-
Coli, which occurs naturally in the intestines and feces of most warm-blooded animals, including
27
humans, is a direct result of fecal contamination when found in water, and a clear indication of
unsafe water, whereas other types of coliform that are not fecal contamination related, including
those commonly found in soil, on the surface of leaves, and in decaying matter, are not
necessarily. Some common health effects of bacterial ingestion include abdominal cramps and
diarrhea. E-Coli is transmitted through fecal-oral ingestion of the bacteria (i.e. drinking),
Additional Sampling Locations in the Municipality of Paraty
The drinking water sources for numerous rural communities, in addition those for the City of
Paraty, were sampled and tested for similar physical characteristics and microbial contamination.
The communities, from where the drinking water sources were sampled, are: Agua Fria, Barra
Grande, Corisco, Patrimonio, Sao Goncalo, Sao Roque, Taquari, Tarituba, and Trindade (See
Figure 2.2).
The water quality of potable waters used in the rural communities was measured by the same
standards used to gauge the potable water quality in the City. In general, the waters in the rural
communities had pH within the 6.5-8.0 range, and turbidity less than 5 NTU (See Figure 3.7 and
3.8). By these parameters, the potable waters in the rural communities were superior to the water
in the City. However, these waters had high concentrations of total coliform and fecal coliform
bacteria, which made them unsafe to drink (See Figure 3.9 and 3.10). None of these waters were
disinfected. The results of water quality analysis, for the city and the rural communities in the
Municipality of Paraty, are summarized in Table 3.2:
Water Quality Parameters Community
No. of
Households Treatment pH Turbidity Total
ColiformFecal
Coliform
Conclusion
City of Paraty 3850 Chlorination Low High Present Present UnsatisfactoryAgua Fria None Normal Normal Present Present UnsatisfactoryBarra Grande 226 None Normal Normal Present Present UnsatisfactoryCorisco 200 None Normal Normal Present Present UnsatisfactoryPatrimonio 125 None Normal Normal Present Present UnsatisfactorySao Goncalo 100 None Normal Normal Present Present UnsatisfactorySao Roque 250 None Normal High Present Present UnsatisfactoryTaquari 300 None Normal Normal Present Present UnsatisfactoryTarituba 107 None Normal Normal Present Present UnsatisfactoryTrindade 250 None Normal Normal Present Present Unsatisfactory
Table 3.2. Drinking water quality results for the City and rural communities in the Municipality of Paraty
36
Figure 3.7. pH of potable waters in the Municipality of Paraty
Figure 3.8. Turbidity of potable waters in the Municipality of Paraty
pH (Potable Water - All Locations)
5.5
6.0
6.5
7.0
7.5
Cab
oclo
Pedr
a Br
anca
Res
ervo
ir
Tap
Wat
er
Agua
Fria
Barra
Gra
nde
Cor
isco
Patri
mon
io
Sao
Gon
calo
Sao
Roq
ue
Taqu
ari
Tarit
uba
Trin
dade
Sample Locations
pH
MaximumMinimumMedian
Turbidity (Potable Water - All Locations)
05
10152025303540455055606570
Cab
oclo
Pedr
a Br
anca
Res
ervo
ir
Tap
Wat
er
Agua
Fria
Barra
Gra
nde
Cor
isco
Patri
mon
io
Sao
Gon
calo
Sao
Roq
ue
Taqu
ari
Tarit
uba
Trin
dade
Sample Locations
Turb
idity
(NTU
)
Maximum
Minimum
Median
37
Figure 3.9. Total coliform of potable waters in the Municipality of Paraty
Figure 3.10. Fecal coliform of potable waters in the Municipality of Paraty
Total Coliform (Potable Water - All Locations)
1
10
100
1,000
10,000
Cab
oclo
Res
ervo
ir
Agua
Fria
Cor
isco
Sao
Gon
calo
Taqu
ari
Trin
dade
Sample Locations
Tota
l Col
iform
(MPN
)
MaximumMinimumMedian
Fecal Coliform (Potable Water - All Locations)
1
10
100
1,000
Cab
oclo
Res
ervo
ir
Agua
Fria
Cor
isco
Sao
Gon
calo
Taqu
ari
Trin
dade
Sample Locations
Feca
l Col
iform
(MPN
)
MaximumMinimumMedian
38
Other Water Quality Tests
The Municipality of Paraty determined, from a series of laboratory tests that were performed in
the past, that many water sources violated the drinking water standards and were in fact unsafe to
drink (See Appendix A-3). Between October 2001 and March 2002, 44 samples of potable water
were collected from various locations within the Municipality of Paraty. Three physical
characteristics (turbidity, color, and odor), and the tests of total and fecal coliform bacteria were
used to determine the quality of the water samples. Of the 44 samples, only 22 samples (17 from
the City of Paraty, 3 from Pantanal, and 2 from Ponte Branca) had been chlorinated.
Of the 44 samples, 28 samples (64%) were determined to be of unsatisfactory quality by at least
one of these parameters. Ten samples (23%) had high concentration of particulate matter; 1
sample (2%) had yellow color. No sample had any detectable odor. Twenty-five samples (57%)
had total coliform bacteria, and 20 of these samples were contaminated with fecal coliform
bacteria. The presence of total coliform bacteria, with 89% occurrence, was the principal cause
for unsatisfactory water quality.
Of the 28 samples that had unsatisfactory water quality, 6 samples (21%) had been chlorinated
for disinfection. Four out of the 6 chlorinated samples were declared unsatisfactory due to the
presence of detectable amounts of coliform bacteria, revealing that the disinfection was not
effective. Two samples from the City of Paraty had both total and fecal coliform bacteria
present, and two had only total coliform present. Two more chlorinated water samples (collected
from Pantanal and Ponte Branca) had no coliform bacteria, suggesting that the chlorination had
been effective, but were declared unsatisfactory due to the high concentration of suspended
solids.
Although 100% of potable water in the City of Paraty was chlorinated, 4 out of the 17 samples
collected in the City (24%) were declared unsatisfactory, due to microbial contamination as well
as high concentration of suspended solids.
39
Conclusion
Numerous water quality analyses reveal that many rural communities in the Municipality of
Paraty, as well as the City of Paraty, consume drinking water that fails to comply with
international drinking water regulations. Two principal causes of substandard water quality are
high turbidity and bacterial contamination. The rural communities, which currently do not treat
their drinking water, must disinfect their drinking water at the least, with chlorine addition for
example.
The City of Paraty must adopt various measures to improve the quality of its drinking water. In
addition to procuring a sufficient supply of drinking water to meet demand at all times, the City
must better protect its drinking water at the sources, and treat the water by filtration and
disinfection. The drinking water must be filtered in order to reduce the turbidity in water, which
frequently rises to unacceptable levels after rainstorms, and a more precise method of
chlorination must be adopted in order to make disinfection of drinking water more effective.
40
3.5. Existing Wastewater Disposal System
Reflecting the City’s preference of drinking water system to drinking water system, Paraty has a
very low percentage (12%) of connection to public sewer system, which lacks sewage treatment.
As a consequence, large quantities of untreated sewage is discharged into two rivers, Pereque-
Acu and Matheus-Nunez, that pass through the City; Jabaquara beach, a popular spot for
swimming that is situated North of the City within walking-distance; and Paraty Bay. It is
estimated that approximately 2,600 m3 of wastewater is discharged into these water bodies on
average, and as much as 7,900 m3 of is discharged in the highly populated summer season.
Wastewater Infrastructure
The City has short networks of sewerage pipe connections, which are mainly used to transport
sewage from individual households into the nearest receiving water body. The sewerage
network is incomplete and run-down, and its exact structure and location is unknown, due to the
misplacement of the plans containing such information.
The incomplete, and often broken, sewerage pipes lead to an additional problem of polluting the
streets with wastewater in the high tides. As the City sits at a low altitude, near sea level, with a
high water table, large parts of the Historical Center is flooded with seawater periodically during
high tidal periods. During these times, wastewater leaks out of broken sewerage pipes and
floods the streets mixed with seawater, before it can discharge into the Bay with reversing tides.
Storm water Infrastructure
While the City has some wastewater collection infrastructure, it has no storm water
infrastructure. The streets in the City are lined with cobblestones, in shapes of a canal, in V or
U-shapes. In congruence with this design, the storm water drains into the Bay naturally by
gravity.
41
3.6. Problems with Wastewater Disposal
The two major problems associated with Paraty’s current mode of wastewater disposal are: (i)
environmental degradation resulting from direct discharge of sewage into surrounding water
bodies, and from tidal inflows that flood the streets with sewage and seawater mixture; and (ii)
health consequences resulting from exposure to such environment. The latter will be discussed
in Section 3.7.
Environmental Degradation
The pollution of surface water bodies, such as rivers and beaches, due to untreated sewage, result
in increased health risks, loss of aesthetics and other amenities, and violation of their intrinsic
values. For those water bodies intended for recreational use, the health risks are very high when
they are polluted with fecal matter. Many environmental regulatory agencies limit the amount of
fecal contamination allowed in recreational water bodies for this reason. For example, the
maximum concentration of fecal coliform bacteria in beach waters, where people swim, is 200
colonies/100ml, and those waters exceeding this limit are required to prohibit these recrational
activities. Therefore, the environmental degradation results in limited recreational activities and
diminished commercial value of the water body.
The loss of aesthetics, due to the discoloration of water and the odor, which becomes more
unpleasant in the summer, also contribute to the diminishment of water body’s commercial
value. The damage to aesthetics also reduces the amenities value and intrinsic value of the water
body.
The environmental degradation not only occurs in the water bodies, due to direct discharge of
wastewater, but also in the streets due to the tidal flows that flood the streets with sea water and
sewage mixture. Similar costs apply to this mode of environmental degradation.
42
Quality of Surrounding Water Bodies
Surface water bodies near the City of Paraty are heavily polluted from human activities. In order
to characterize the quality of these surface water bodies, samples were collected from numerous
locations and tested. The following is the description and analysis of the surrounding surface
water bodies in the City.
Sampling Locations
Water samples were collected from Jabaquara Beach, Matheus-Nunez River, and Pereque-Acu
River (referred as “Jabaquara Beach,” “Matheus River,” and “Pereque River,” respectively), and
tested. Samples were also collected from an open ditch (designated “Sewer Stream”) that carries
raw sewage through Mangueira and discharges into the Paraty Bay. Jabaquara Beach water was
sampled 11 times, at the knee level near the most populated places. Matheus River, Pereque
River, and Sewer Stream waters were sampled 7, 9, and 4 times, respectively. The Matheus
River water was sampled at the riverbank, near small boats. The Pereque River water was
sampled from a bridge, at the center of the river’s cross-section. The Sewer Stream water was
sampled similarly at the middle of the cross-section, from a walkway crossing the ditch.
Water Quality Parameters
The water quality parameters tested are pH, turbidity, suspended solids, chemical oxygen
demand (COD), total coliform, and fecal coliform bacteria concentrations. The water quality
measurements for Jabaquara Beach samples are compared against surface water criteria for
coastal waters designated for aquatic life, recreation, navigation, and industrial water supply (See
Table 3.3). Similarly, the water quality measurements for Pereque River and Matheus River
samples are compared against surface water criteria for waters designated for aquatic life,
recreation, navigation, and industrial and agricultural water supply (See Table 3.4). The Sewer
Stream samples, on the other hand, are compared to the raw sewage sampled in the City of
Paraty (See Table 3.5).
43
Beach
Coastal water standards, EPA Connecticut Designated Use Habitat for marine fish and other aquatic life and wildlife; shell fish
harvesting; recreation; navigation; and industrial water supply pH 6.8-8.5 Turbidity (NTU) None other than of natural origin Total suspended solids (mg/l) None other than of natural origin Fecal coliform bacteria (colonies/100 ml)
Geometric mean of 200/100 ml for summer primary contact recreation
Table 3.3. Beach water quality criteria
River Interim national river
water quality standards, Malaysia
Water quality constituents and standards, EPA Kansas
Surface water standards, EPA Connecticut
Designated Use Aquatic life; recreation Aquatic life; recreation Habitat for fish and other aquatic life and wildlife; recreation; navigation; and industrial and agricultural water supply
COD (mg/l) 25 Total coliform bacteria (colonies/100ml)
5,000
Fecal coliform bacteria (colonies/100ml)
100 Geometric mean of 200/100 ml for summer primary contact recreation; 2000/100 ml for winter primary contact recreation or secondary contact recreation
All four surface water bodies show fecal coliform concentrations that suggest contamination
from sewer discharge. Among the four, Jabaquara Beach shows the least amount of
contamination, most likely benefited by tidal dilution. Matheus River and Pereque River are
approximately equally contaminated, and Sewer Stream shows characteristics of diluted raw
sewage.
Jabaquara Beach, a popular recreational water body where people swim, that is within walking
distance from the City of Paraty, is inadequate for primary recreation, which includes swimming.
Jabaquara Beach water has a slightly low pH, adequate levels of turbidity and suspended solids,
and high COD.
Neither Matheus Rivers nor Pereque River is adequate for secondary recreation, due to high
levels of fecal contamination. Matheus River showed acceptable pH, but especially high COD
level that is most likely due to oil spills from small boats anchored at the riverbank. Pereque
River had pH that is in the lower end of the acceptable range, and low COD that is within
acceptable range most of the time. The turbidity and suspended solids for both Rivers suggest
that they are often, but not always, in the safe range for aquatic life.
Conclusion
From the water quality analysis above, it is evident that the City’s current mode of wastewater
disposal degrades its surface waters, rendering Jabaquara Beach unsafe for swimming, and
Matheus River and Pereque River unsafe for all aquatic sports. The uncontrolled disposal of
wastewater damages the aesthetics of the rivers, and reduces the commercial value of the
environment. The source of pollution must be controlled in order to preserve the environment
from further degradation, and therefore an appropriate treatment and discharge of the City’s
wastewater is critical. The collection and treatment of wastewater is expected to limit pollution
of the surface waters, as well as the streets, in the City of Paraty.
53
3.7. Problems with Public Health - Diarrhea
A direct consequence of poor potable water quality and polluted environment is the negative
impact on public health. Of many different diseases and illnesses, diarrhea is the most widely
studied public health problem that is associated with poor water and sanitation.
Incidence
A total of 443 diarrhea cases were recorded at local hospital and health clinics in the
Municipality of Paraty, from Sept. 1, 2002 to Dec. 28, 2002, according to an epidemiological
study conducted by Wilsa Mary S. Barreto (Barreto, 2003). Of these 443 cases, 228 cases (51%)
were of those individuals living in the City of Paraty, 204 cases (46%) of individuals living in the
rural areas, and 11 cases (2%) of individuals from outside. Among the 228 people from the City
of Paraty, 60% were from Mangueira and Ilha das Cobras, the poorer parts of the City.
Number of diarrhea cases Area
Population In 4 months In 1 year
Probability of diarrhea incidence per person
Urban 1,5000 51% 228 680 4.6% Mangueira and Ilha das Cobras
7,500 60% 137 410 5.5%
Other 7,500 40% 91 270 3.6% Rural 1,5000 46% 204 610 4.1% Other 2% 11 30 Municipality Total 30,000 100% 443 1,300 4.4%
Table 3.6. Number of diarrhea cases within Municipality of Paraty by location1
Approximately 111 diarrhea cases are treated in the health clinics each month, and
approximately 1,330 cases are treated each year, if the incidence of diarrhea is assumed constant
throughout the year. Furthermore, each person in the Municipality of Paraty has greater than 4%
probability of suffering from diarrhea each year, if each person is assumed to suffer from
diarrhea not more than once a year. The probability is greatest for the urban poor, those living in
Mangueira and Ilha das Cobras, who have greater than 5% likelihood of suffering from diarrhea
in a year.
1 Number of diarrhea cases, which were registered at local hospital and health clinics between September 1, 2002 and December 28, 2002.
54
More importantly, the number of diarrhea cases reported above does not account for all diarrhea
cases in Paraty, but only those that received care at the local hospital and health clinics. The
actual number of diarrhea cases is expected to be much higher, because many people treat their
illnesses at home.
It is expected that the poor and the rural population are less likely to visit health clinics, due to
lack of time and money. Even though basic health services are provided free of charge in Paraty,
the time required to go to health clinics can be costly. This cost of time is especially significant
for the poor and those living in rural areas, farther away from the health clinics. Therefore, the
numbers of diarrhea cases in the poorer areas (Mangueira and Ilha das Cobras), and the rural
areas are likely to be much higher than the numbers reported.
The higher proportion of diarrhea cases in the City than in the rural areas suggests that: (i) the
disinfection of City’s drinking water is often ineffective; (ii) adequate sanitation is as important
as, if not more than, clean drinking water supply. Although the common sense expects the
number of diarrhea cases to be lower for the urban population, which drinks disinfected drinking
water, than for the rural population, which does not, the study indicates that this is not so. In
fact, the incidence of diarrhea for the urban population is higher at 4.6% than the 4.1% for the
rural population. It is likely that the disinfection of City’s drinking water with chlorine addition
is ineffective and therefore does not benefit the urban population. The test of residual chlorine
concentration in City’s drinking water, which indicated zero residual chlorine concentration,
reinforces this speculation.
It is also likely that environmental pollution, which is more serious in the City than the in rural
areas, accounts for larger number of diarrhea cases in the urban population. The City, occupied
by half of the Municipality’s population, discharges large quantities of untreated sewage
everyday, severely polluting its waters. In contrast, the rural areas have smaller population
density, and their sewage disposal is likely to be in better control. Therefore, the more polluted
environment in the City could account for its higher diarrhea incidence, suggesting furthermore
that adequate sanitation is as important as the supply of clean drinking water.
55
Morbidity
As much as 9% of diarrhea cases studied were serious, with two or more signs of serious
dehydration, which can be life-threatening without proper and timely treatment. Approximately
7% of diarrhea cases showed two or more signs of dehydration that were less serious, and 57%
of the cases were mild with no sign of dehydration. The seriousness of these diarrhea cases was
determined from the types of medical treatment (i.e. “Plans”) received by the patients. The age
distribution of the patients was not studied.
Plan A Plan B Plan C Plan Ign. Sum Total Number of Cases (by Plan Type) = 254 31 41 117 443
Percent of Cases (by Plan Type) = 57% 7% 9% 26% 100% Plan A: No sign of dehydration Plan B: Two or more signs of dehydration Plan C: Two or more signs, including one which shows serious dehydration
Table 3.7. Number of diarrhea cases within Municipality of Paraty by morbidity
Conclusion
Diarrhea, a widely studied indicator of water and sanitation-related diseases, is prevalent in both
the urban and the rural areas of Paraty. According to this study of diarrhea incidence in Paraty,
the most severely affected areas are Mangueira and Ilha das Cobras, the more densely populated,
low-income areas within the City of Paraty.
It is assumed that a significant proportion of diarrhea cases is caused by waterborne pathogens,
although it is difficult to estimate the exact proportion that is caused by the consumption of
poorly disinfected drinking water, or by the contact with polluted surface waters (Payment and
Hunter, 2001). For the City of Paraty, it is speculated that both the ineffectively disinfected
drinking water, and the highly polluted surface waters are the causes of diarrhea and other water
and sanitation related diseases.
56
3.8. Other Problems
In addition to the problems associated with potable water supply, wastewater disposal, and
related health consequences, Paraty suffers from the following problems that are typical and
common in many developing areas: (i) commercial and financial problems; and (ii) technical and
operational problems (World Bank qtd. in US Dept. of Commerce, 1999).
Commercial and Financial
The commercial and financial problems observed in the City of Paraty are: (i) limited
consumption metering; (ii) billing based on property value or lot size, regardless of the amount
of water consumed; (iii) under-priced water; and (iv) commercial losses that reflect the high
levels of unaccounted-for water.
The City of Paraty, which provides connection to public water supply to nearly 100 % of its
population, has water meters connected to only 44% of those water connections (Prefeitura,
“Laudo,” 2002). In addition, these water meters, which were read in the past, are no longer read.
The City claims that it lacks personnel to read the water meters, and that many water meters are
broken or malfunctioning.
The City currently sets tariffs for water and sewage according to property size, since the
consumption metering has been discontinued. On average, small houses in Mangueira or Ilha
das Cobras, are billed approximately R$3 to R$5 per month, and larger houses in the Historical
Center and Jabaquara are billed approximately R$7 per month. Commercial entities are billed
much more; a bakery would be billed R$100 each month, for example. On the other hand,
farms, which are often the largest users of water, are supplied with water free of charge (Reis,
2003).
The City’s current tariff for domestic and agricultural water consumption is under-priced. For
example, monthly billing of R$7 per month per household is much lower than R$0.73 per m3 of
water consumed, and R$0.87 per m3 of sewage discharged, which are average volumetric tariff
charged by CEDAE (US Dept. of Commerce, 1999). Assuming that a household consists of an
57
average of 4 people, and that each person consumes 180 liters of water each day, each household
consumes approximately 22 m3 each month. Therefore, the City’s current tariff of R$7 per
month per household is equal to R$0.32 per m3 of water consumed, much lower than the amount
that is charged in most of the State.
The City’s suffers from commercial loss (unaccounted-for water) due to poorly enforced billing.
Currently, approximately 30% of the bills invoiced are not collected, and the uncollected bills
amounts to approximately R$190,000 each year (Prefeitura, “Laudo,” 2002). The Municipality
of Paraty is currently making efforts to increase the percentage of collected bills to 80% over the
next 10 years, and to 85% in 5 additional years, by installing water meters and holding every
household accountable for its consumption (Reis, 2003).
Year Tot Collected (R$) Tot Invoiced (R$) % Collected Annual Loss (R$) 2000 505,000 730,000 69 225,000 2001 540,000 750,000 72 210,000 2002 415,000 556,000 75 141,000 Average 487,000 679,000 72 192,000
Table 3.8. Tariffs for water and sanitation invoiced and collected by the City of Paraty
Technical and Operational
Inadequate preventive and regular maintenance of water and wastewater infrastructure is the
main technical and operational problem that is observed in Paraty. The inadequate maintenance
of water supply infrastructure is evident from the large quantities of water loss due to leakage
from broken supply pipes. The inadequate maintenance of the few wastewater infrastructure that
exist is also observed from the leakage of sewage in the streets.
58
3.9. Summary of Problems
City of Paraty currently suffers from poor public health, polluted surface waters, and degraded
aesthetics and commercial value of the environment, all of which are the consequences of poor
water and sanitation systems. In addition, the City’s goal of becoming a UNESCO World
Heritage Site has been deferred due to the lack of functioning sanitation system in the Historical
Center. In order to mitigate these problems, improve the quality of life, and foster economic
growth in the City, the City’s water and wastewater infrastructure must be improved.
Areas of improvement in the potable water supply are: (i) treatment of drinking water, (ii)
protection of drinking water sources, and (iii) procurement of sufficient drinking water supply. It
is evident that the City’s potable water must be filtered and better disinfected in order to make it
safe for drinking, and that the drinking water sources must be isolated in order to prevent
accidental contamination of the source waters. Furthermore, to improve the quality of life for the
local population, as well as the tourists, water shortages must be eliminated.
Areas of improvement in wastewater supply are: (i) collection of wastewater collection, and (ii)
treatment of wastewater. New wastewater infrastructure must be put in place to collect sewage,
and a new wastewater treatment plant must be constructed in order to treat the wastewater before
it can be safely discharged into the surrounding waters.
59
CHAPTER 4 - WATER AND SANITATION IMPROVEMENTS
This chapter recommends water and sanitation improvements that are necessary to mitigate
Paraty’s current water and sanitation-related problems, which were identified and described in
detail in the preceding chapter. The population/area(s) to service, the type(s) of improvement,
and the time(s) of development are considered. The costs of improvements are estimated and the
City’s capacity to recover these costs is analyzed by estimating new water and sewage tariff, and
the people’s willingness to pay.
4.1. Initial Considerations
Although the hope is to achieve universal coverage, providing adequate water and sanitation
services to all, this cannot be achieved at once. Therefore, it is necessary to determine which
community to service first, with which service, and when to develop these services, adhering to
Paraty’s objectives and priorities. It is assumed that there is, at the base of Paraty’s objectives
and priorities, a goal to provide water and sanitation services to the maximum number of people
with the least amount of time and money.
Population/Area(s) to Service
Urban vs. Rural
The wastewater infrastructure and treatment plant is to be constructed for the City, rather than for
other rural communities in the Municipality, because the City has a more serious and imminent
need for sanitation improvements. While the City suffers from severe environmental
degradation, which exposes large numbers of local people and tourists to considerable health
risks, due to uncontrolled discharge of human wastes, it is assumed that rural communities,
which have smaller population density, have better control of their wastes and are thus in a
healthier condition. More importantly, sewage collection and treatment in rural areas is seldom
economically feasible, and hence the use of septic tanks is recommended and commonly used in
rural areas.
60
While sanitation improvements in the City are justified thus, the improvement of the City’s
drinking water treatment is justified by Paraty’s objective to service a larger number of people
with less time and money. It is evident, from the water quality analysis, that both the urban and
the rural communities are in need of better drinking water treatment. The rural communities
need of disinfection for their drinking water, at the least, which they do not have, and the City,
which does have disinfection, needs a more reliable method of disinfection, and treatment by
filtration, because its water quality often falls substandard. Given this situation of similar needs,
the drinking water treatment project for the City is preferred from the social and economic
perspective.
The drinking water treatment for the City is preferred to those for rural communities due to the
differences in population. The largest rural community in the Municipality of Paraty does not
have more than 300 to 400 households (1200 to 1400 persons), while the City holds more than
3,800 households. This means that one water and sanitation project in the City services
approximately 10 times the population of a rural community. Conversely, more than 10 separate
water and wastewater treatment facilities in different rural communities are needed to service the
equivalent urban population. Moreover, one large project costs less than 10 smaller projects with
1/10 its capacity, due to economy of scale, and are typically more profitable than smaller
projects. Therefore, it is justifiable to service the larger of two communities when two
communities have similar needs.
The City’s water and sanitation improvements are also valid from the health perspective.
According to the study of diarrhea incidence in the Municipality of Paraty, there was a higher
number of diarrhea cases in the City, than in the rural communities, and the low-income areas of
the City, Mangueira and Ilha das Cobras, had the highest diarrhea incidence per capita.
Therefore, the water and sanitation projects are most critical in the City, especially in Mangueira
and Ilha das Cobras.
Jabaquara
Jabaquara is excluded from the City’s development of wastewater collection infrastructure and
treatment plant, due to geographic constraints. Because Jabaquara is located North of Pereque
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River, separated from the rest of the City by a hill and a narrow band of water, transporting its
wastewater to the City’s treatment plant, to be located in Ilha das Cobras, would be too costly.
Therefore, a separate wastewater system is recommended for Jabaquara.
On the other hand, Jabaquara can be included in the City’s drinking water supply system, to
receive treated drinking water from the City’s future drinking water treatment plant, which is to
be located on a hill, next to the City’s existing reservoir. Although Jabaquara currently brings its
drinking water directly from Caboclo intake, rather than from the City’s reservoir, a supply pipe
could be constructed to connect Jabaquara to the future treatment plant. The water would flow
downhill by gravity from the future treatment plant to Jabaquara, which has an elevation near sea
level.
Development Priorities
Due to high capital costs involved with water and sanitation developments, it is often economical
to divide the development projects into a number of stages, and undertake one project, or one
section of a project, at a time. A project of the highest priority would be developed in stage 1,
followed by projects of lower priority (i.e. those projects, the time of completion of which are of
less consequence).
Water Supply vs. Sanitation
In the City of Paraty, the need of wastewater collection and treatment is considered more serious
and imminent than the need for better drinking water treatment, for the following two reasons: (i)
a functioning wastewater collection and treatment system at the Historical Center is necessary in
the near future for the qualification of UNESCO World Heritage Site; and (ii) while there is a
drinking water alternative, the bottled water, there is no alternative for wastewater collection and
treatment. Therefore, in a situation where the undertaking of both water and wastewater projects
is not economically feasible, the City is to commence its wastewater project first.
Wastewater Collection Infrastructure vs. Wastewater Treatment Plant
The construction of wastewater collection infrastructure and the wastewater treatment plant is to
be undertaken concurrently, since one is useless without the other.
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4.2. Recommendations
The previous chapter identified the following improvements, which are essential in the City of
Paraty: (i) a wastewater infrastructure and a treatment plant for the collection and treatment of
wastewater; and (ii) a drinking water treatment plant with filtration and disinfection, for better
treatment of drinking water.
Wastewater Collection System
A gravity sewer system is recommended for the collection of wastewater (Choi, 2003). In a
gravity sewer system, wastewater is transported by gravity flow to treatment facilities. The
gravity flow is maintained by the slopes of the sewer pipes, which are designed to maintain the
minimum “self-cleansing” velocity of approximately 0.6 m/s. Due to the slopes required and the
depth of the sewer pipes, gravity sewers often require lift station pumps to transport wastewater
from low to high points, so that flow can proceed by gravity again. Gravity sewer systems
generally require less maintenance than other sewer collection systems, such as a low-pressure
force main system. In addition, a gravity system can handle large variations in flow, and is
readily adaptive for growth and change within the sewer district (Pleasanton, 2001).
Wastewater Treatment Plant
A chemically enhanced primary treatment (CEPT) plant is recommended for the treatment of the
City’s wastewater (Kfouri and Kweon, 2003). CEPT is the process by which chemical
coagulants are added to primary sedimentation basins in order to enhance the treatment
efficiency (i.e. removal of solids, organic matter, and nutrients from the wastewater). CEPT
costs minimally more than primary treatment, and half as much as secondary treatment, but its
efficiency is highly competitive with biological secondary treatment. “CEPT is ideal for a
coastal city since the removal of total suspended solids is very high, and the decrease in
biochemical oxygen demand is sufficient so as not to impact oxygen concentrations in the ocean”
(Chagnon, 2002).
The CEPT plant is to be located in an empty lot in Ilha das Cobras (See Area 1 in Figure 4.1).
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Figure 4.1. Possible location of wastewater treatment plant and drinking water plant 1
Drinking Water Treatment Plant
Different alternatives of filtration and disinfection are to be considered by the City of Paraty, for
the treatment of the City’s drinking water. Some of the treatment options include conventional
filtration, direct filtration, slow sand filtration, and diatomaceous earth (DE) filtration. The
descriptions of each follow:
Conventional Filtration
The conventional filtration consists of rapid mix coagulation, flocculation, sedimentation, and
gravity filtration. Common filter media include sand, dual-media and tri-media. Conventional
filtration is the most widely used technology for treating surface water supplies for turbidity and
microbial contaminants, and has the advantage that it can treat a wide range of water qualities.
However, it has the disadvantage that it requires advanced operator skill and has high monitoring
requirements (US EPA, “Small System,” 1997).
1 1=Location of wastewater treatment plant; 2=Location of drinking water treatment plant.
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Direct Filtration
Direct filtration is conventional filtration minus the sedimentation step. In-line filtration is the
simplest form of direct filtration and consists of filters preceded by direct influent chemical feed
and static mixing. In general, direct filtration requires low turbidity raw water and is attractive
because of its low cost relative to conventional treatment. However, similar to conventional
filtration, direct filtration requires advanced operator skill and has high monitoring requirements.
The performance of direct filtration is extremely sensitive to the proper management of the
coagulation chemistry, and if the coagulation step is disrupted or improperly executed, the
removal efficiencies for turbidity and microbial contaminants decrease dramatically in a matter
of minutes (US EPA, “Small System,” 1997).
Slow Sand Filtration
Slow sand filtration employs a sand filter with a large cross-sectional area, which results in a low
filtration rate. Slow sand filtration also employs a biological slime layer, called the
“schumutzdecke,” which develops over time on top of the sand. The schumutzdecke assists in
the removal of suspended organic materials and microorganisms, by biodegradation and other
biological processes, instead of relying solely on simple filtration or physico-chemical sorption.
An advantage of slow sand filtration is that no backwashing is necessary for slow sand filters.
When a predetermined duration, headloss or effluent turbidity is reached, the top few centimeters
of the sand are scraped off. Other advantages of slow sand filtration include its low maintenance
requirements (since it does not require backwashing and requires less frequent cleaning) and the
fact that its efficiency does not depend on actions of the operator. A disadvantage of slow sand
filtration is that large systems have large land requirements. Slow sand filters are simple, and
easily used by small systems (US EPA, “Small System,” 1997).
Diatomaceous Earth (DE) Filtration
Diatomaceous earth (DE) filtration involves a filter cake build-up on a fabric filter element or
septum. The DE is a powdery, siliceous material that, on a particle level, is porous, multi-
shaped, angular, and varies in width between 5 and 60 microns. The DE filter cake is subject to
cracking and must be supplemented by a continuous body feed of diatomite to maintain porosity
of the filter. Problems inherent in maintaining the filter cake have limited the use of DE
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filtration. The advantage of DE is that it does not require coagulants. A disadvantage is that
advanced operator skill is required for filtration efficiency (US EPA, “Small System,” 1997).
Summary
Land area permitting, the slow sand filtration would be the optimal system for the City of Paraty,
since it is cost-effective and does not require advanced operator skills. However, the City should
compare the different alternatives of filtration, described above, and select a system that best
satisfies the City’s needs. In the cost analysis, which is to follow, the conservative costs of a
conventional filtration plant are used.
The most convenient location for the drinking water treatment plant is next to the City’s
reservoir, since this is where the waters from two sources, Pedra Branca and Caboclo, are
combined, disinfected, and distributed to the City (See Area 2 in Figure 4.1).
Development Sequence
The wastewater collection infrastructure and treatment plant are to be constructed concurrently in
three stages for the City of Paraty, excluding the Jabaquara area. The Historical Center is to be
developed in the first stage; Mangueira and Ilha das Cobras in the second stage; and the Old City
and rest of the City in the third stage. Each development stage is to last approximately 2 years.
The incremental development of the CEPT plant is made possible by its ease of implementation
and expansion.
The drinking water treatment plant, with the capacity for the entire City of Paraty including
Jabaquara, is to be constructed in one stage, since its expansion is likely to be more difficult.
The drinking water treatment plant will be constructed after the completion of the wastewater
collection infrastructure and treatment plant. However, since there is an immediate need for a
more precise method of chlorination, the drinking water disinfection system is to be upgraded
immediately, with a flow meter and an automated chlorinator, for example. In addition, the
drinking water intake points are to be fenced around the perimeter, in order to protect the
integrity of the drinking water.
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The earliest feasible time for the construction of drinking water treatment plant is to be
determined by comparing the costs of constructing the drinking water treatment plant at different
years after the completion of the wastewater infrastructure developments. Four scenarios of
development sequence are considered, as shown in Table 4.1:
Table 4.1. Four scenarios of development sequence for wastewater and drinking water infrastructure1
Scenario 1 assumes an accelerated project, in which all development is completed in a four-year
period, each development stage lasting one year. Scenarios 2, 3 and 4 estimate that each
development stage lasts two years. Scenario 2 assumes that all developments will be completed
in 8 years, during which time the completion of each development stage is immediately followed
by the development of the subsequent stage. Scenario 3 assumes one year of no development
between the completion of the development of wastewater infrastructure and the development of
drinking water treatment plant, and Scenario 4 assumes two years of no development.
4.3. Design Parameters
Two important parameters in the design of the wastewater collection infrastructure and treatment
plant, and the drinking water treatment plant are the population in the City of Paraty, and an
average consumption of water per capita. The flow demand for the wastewater infrastructure
and treatment plant, and the drinking water treatment plant are estimated from these two
parameters:
Daily flow = (Daily water consumption per capita) x (Population)
1 WW1 = development stage 1 of wastewater infrastructure and treatment plant; WW2 = development stage 2; WW3 = development stage 3; and DW = development of drinking water treatment plant
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Population
The population in the City of Paraty is assumed to increase in the summer. The rough estimates
of the average annual population, and summertime population are listed in Table 4.2 below:
Area Average Summertime Increase Peak (Summer) Jabaquara (excluded from WW design) 1,500 3x 4,500 Historical Center 3,000 3x 9,000 Mangueira 4,500 1x 4,500 Ilha das Cobras 3,000 1x 3,000 Old City 3,000 3x 9,000 Total Urban Population 15,000 30,000
Table 4.2. Average annual population and the peak summertime population for the City of Paraty
As indicated in the table above, most areas in the City are expected to experience a 3-fold
increase in population during summer. However, the population in Mangueira and Ilha das
Cobras is expected to remain constant since these areas are primarily residential areas for the
local people. The annual population growth rate is approximately 0.8%, estimated from the
average growth rate in the State of Rio de Janeiro (CEPIS, 2002).
Consumption
The design flow for the wastewater and the drinking water systems are estimated from the daily
potable water consumption of 180 liters per capita (Prefeitura, “Laudo,” 2002). The amount of
wastewater produced is assumed to be approximately equal to the potable water consumption.
The flow demand for different stages of development for the wastewater collection infrastructure
and treatment plant and for the one-stage development of the drinking water treatment plant are
estimated below:
Development Stage Development Area Design Flow (m^3/day) WW 1 Historical Center 1,620 WW 2 Mangueira and Ilha das Cobras 1,350 WW 3 Old City 1,620 DW City of Paraty including Jabaquara 5,400
Table 4.3. Summertime average daily flow for water and wastewater treatment design for the City of Paraty1
1 Design flow corresponds to summertime average flow.
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4.4. Cost Analysis
Project Cost
The capital cost and operation and maintenance (O&M) costs of the wastewater infrastructure
and treatment plant and the drinking water treatment plant are derived from a number sources.
All costs are assumed to be linear with flow capacity, and a conversion rate of US$1.00 = R$1.00
is used to convert US costs to Brazilian costs. The exchange rate of US Dollar to Brazilian Real
is approximately US$1.00 = R$3.11 (X-rates.com, 2003). However, the cost of equipments and
labor in Brazil is assumed to be approximately 1/3 of the cost in the US (Tsukamoto, 2003).
Therefore, the true value of US$1.00 is approximately equal to the value of R$1.00.
Wastewater Collection and Treatment
The capital cost of wastewater collection infrastructure includes: piping, pump stations,
manholes, and associated construction costs. The capital and O&M costs of wastewater
infrastructure are estimated from US costs (Choi, 2003).
The capital cost of wastewater treatment includes: CEPT tanks, chlorination and dechlorination
chambers, sludge dewatering units and drying beds, and associated construction costs. The
O&M cost includes: chemical costs for CEPT and disinfection, as well as sludge treatment and
disposal costs. The costs of CEPT and sludge treatment and disposal are Brazilian costs adapted
from Tatui-CEAGESP Wastewater Treatment Facility, Brazil (Cabral et al., 1999). The
disinfection cost of the wastewater effluent, including chlorination and dechlorination, is US cost
adapted from the US EPA (US EPA, qtd. in Kfouri and Kweon, 2003). The capital cost and
O&M cost of wastewater collection infrastructure and treatment plant are summarized in Table
4.4 below:
Total Cost for Wastewater Collection Infrastructure and Treatment Plant WW Infrastructure CC 2,720 R$1000 WW Treatment CC 1,292 R$1000 Total WW Capital Cost 4,011 R$1000 WW Infrastructure O&M Cost 436 R$1000/yr WW Treatment O&M Cost 35 R$1000/yr Total WW Annual O&M Cost 472 R$1000/yr
Table 4.4. Total capital cost and O&M cost for wastewater collection infrastructure and treatment plant
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Drinking Water Treatment
The capital and O&M costs of a conventional drinking water treatment plant, consisting of rapid
mixing, flocculation, sedimentation, chlorination, filtration, contact basin, chemical feed
systems, and finished water storage, are adapted from typical US costs estimated by US EPA
(US EPA, 1999). The cost for a new finished water storage tank is included since the City’s
existing reservoir, constructed in 1975, is rundown and approaching the end of its lifetime. The
following costs are neglected due to lack of information: (i) current O&M cost for chlorination;
(ii) capital cost and O&M cost for interim upgrade of drinking water disinfection system; (iii) all
costs associated with drinking water infrastructure.
The capital cost and O&M cost of a new drinking water treatment plant with conventional
filtration and chlorination are summarized in Table 4.5 below:
Total Cost for Drinking Water Treatment Plant DW Treatment CC 1,057 R$1000 Total DW Capital Cost 1,057 R$1000 DW Treatment O&M Cost 395 R$1000/yr Total DW Annual O&M Cost 395 R$1000/yr
Table 4.5. Total capital cost and O&M cost for drinking water treatment plant
Financial Analysis
The above costs are incorporated into four scenarios of development sequence, shown in Table
4.1, and evaluated assuming a project life of 30 years and annual interest rates of 5% and 10%
(See Appendix D). Equivalent uniform annual cost (EUAC), defined as the amount of money
which, paid in equal annual installments over the life of a project, would pay for the project, is
referred as average annual cost in this analysis. Average annual cost and benefit/cost ratio of the
projects are computed and used to determine the minimum water and sewage tariff required to
fully recover costs, as well as the earliest feasible time for the construction of drinking water
treatment plant.
Break-Even Tariff for Water and Sewage
In the following analysis, the break-even tariff for water and sewage, which reflects the
minimum amount of revenue required to fully recover the costs, is estimated by setting the City’s
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annual revenue to equal the average annual cost (i.e. by setting the benefit/cost ratio equal to 1).
An important consideration in this computation is that the break-even tariffs are computed
accounting for the fact that the City collects only 70% of its invoiced tariffs (See Section 3.8).
The break-even tariffs for water and sewage, for the four scenarios of development sequence
listed in Table 4.1, are summarized in Table 4.6 below:
Development Sequence Scenario
Annual Cost (R$1000)
Annual Revenue (R$1000)
Water and Sewage Tariff (R$/m^3)
I = 5% I = 10% I = 5% I = 10% I = 5% I = 10% 1 1,086 1,226 1,086 1,226 1.57 1.78 2 976 1,058 976 1,058 1.42 1.53 3 955 1,030 955 1,030 1.38 1.49 4 934 1,004 934 1,004 1.35 1.46
Table 4.6. Equivalent uniform annual cost and break-even tariff for water and sewage
According to this financial analysis, the annual cost is greatest for Scenario 1, in which all
developments, including wastewater infrastructure and treatment plant and drinking water
treatment plant, are completed within a period of 4 years. Under Scenario 1, an average water
and sewage tariff, required to fully recover the project costs, is R$1.57/m3 at 5% annual interest
rate, and R$1.78/m3 at 10% annual interest rate. The annual cost decreases with extended
duration of water and wastewater developments, and the minimum water and sewage tariff
decreases correspondingly.
Economic Feasibility of Projects when Water and Sewage Tariff = R$1.60/m3
The economic feasibility of the projects is also analyzed for the case that uses average water and
sewage tariffs previously determined by CEDAE. CEDAE charges an average tariff of
R$0.73/m3 for drinking water, and R$0.87/m3 for sewage (US Dept. of Commerce, 1999). The
combined tariff is R$1.60/m3. The average annual revenue is estimated from the sum of water
and sewage tariffs collected each year, which is approximately 70% of the invoiced tariffs. The
benefit/cost ratio, an important indicator of the economic feasibility of the projects, is estimated
by dividing revenues by costs. The average annual revenue and the benefit/cost ratios are listed
in Table 4.7 below:
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Development Sequence Scenario
Annual Cost (R$1000)
Annual Revenue (R$1000)
Benefit/Cost Ratio
I = 5% I = 10% I = 5% I = 10% I = 5% I = 10% 1 1,086 1,226 1,209 1,185 1.1 1.0 2 976 1,058 1,209 1,185 1.2 1.1 3 955 1,030 1,209 1,185 1.3 1.2 4 934 1,004 1,209 1,185 1.3 1.2
Table 4.7. Benefit/cost ratio for water and sewage tariff = R$ 1.60/m^3
According to this analysis, the water and sewage tariff of R$1.60/m3 produces an average annual
revenue of R$1.2 million at annual interest rates of 5% and 10%, and the benefit/cost ratios that
range from 1.0 to 1.3. Therefore, all four scenarios of development sequence are economically
feasible, at either interest rates, when the tariff for water and sewage is equal to R$1.60/m3.
Summary
The minimum water and sewage tariff required for full recovery of costs, which include the costs
of operation, maintenance, and administration as well as current debt service obligations, is
approximately R$1.80/m3 when the annual interest rate is 10%. This tariff is approximately
equivalent to R$38/household-month for a 4-person household, and about 5 to 10 times the
City’s current tariff for residential use. At the same time, it is about 1/10 of the City’s current
tariff for commercial use.
4.5. Willingness to Pay Analysis
Although the study of willingness to pay (WTP) for improvements in water and sanitation was
not performed in the City of Paraty, due to limited time and resources, it can be estimated based
on a number of economic indicators.
Assumptions
The basic underlying assumption in this study is that the WTP is approximately equal to the sum
of the existing water and sewage tariff paid, the cost of bottled drinking water purchased, and the
minimum wage lost due to water and sanitation-related illnesses:
WTP = existing tariff + cost of bottled drinking water + minimum wage lost to illness
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Distribution of Income
Since the WTP is closely related to household income, it is estimated separately for the low-
income households in Mangueira and Ilha das Cobras, and for the mid- to high-income
households in Historical Center, and Old City. The WTP in the low-income areas is expected to
be lower than that in the high-income areas. The WTP in Jabaquara, which is a relatively high-
income community, is estimated separately, since its sanitation system will not be connected
with the City’s public sewer system.
Mangueira and Ilha das Cobras
The average current tariff for water and sewage in Mangueira and Ilha das Cobras is
approximately R$3/household-month.
It is assumed that half of the Mangueira and Ilha das Cobras population buys bottled water for
drinking. Or, it is assumed that the entire Mangueira and Ilha das Cobras population buys
bottled water for approximately half of the month, on average. Additionally, it is assumed that
each person drinks 2 liters of water each day. Therefore, in Mangueira and Ilha das Cobras, a 4-
person household, which consumes 240 liters of water each month for drinking, buys 120 liters
of the bottled water each month. Since a 20-liter bottle of water purchased and delivered to
individual households costs R$3 in Paraty, the cost of bottled water is approximately
R$18/household-month.
Due to a comparatively high diarrhea incidence in Mangueira and Ilha das Cobras, it is assumed
that an income-earning member in each household loses a day of work each month due to a
water-related illness of his/her own or that of his/her child. Assuming that the monthly minimum
wage in Mangueira and Ilha das Cobras is approximately equal to the monthly minimum wage of
R$240 in Brazil, the cost of minimum wage lost to water and sanitation-related illness is
approximately R$8/household-month.
WTP (Mangueira and Ilha das Cobras) = 3 + 18 + 8 = R$29/household-month
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The WTP, for the Mangueira and Ilha das Cobras population, is approximately R$29/household-
month.
Historical Center and Old City
Since the tariff for water and sewage in the City is currently determined from property value (i.e.
lot size), and the houses in Historical Center, and Old City are generally larger, the average
monthly tariff is higher for the households in these areas. The average monthly tariff for water
and sewage in Historical Center, and Old City is approximately R$7/household.
It is assumed that mid- to high-income households drink only bottled water. Therefore, each
household in Historical Center and Old City purchases approximately 240 liters of bottled water,
and the cost of bottled water is approximately $R36/household-month.
It is assumed that the minimum wage in Historical Center, and Old City is generally higher than
the minimum wage in Mangueira and Ilha das Cobras. However, it is also assumed that the
population in these areas are less afflicted by water and sanitation-related illnesses. These two
assumptions considered, it is estimated that the loss of wage due to water and sanitation-illnesses
in these areas is also approximately R$8/household-month.
WTP (Historical Center, and Old City) = 7 + 36 + 8 = R$51/household-month
The WTP, for the Historical Center and Old City population, is approximately R$51/household-
month.
Jabaquara
Since Jabaquara is a relatively high-income community, with tourism as its major industry, the
WTP of its population is expected to be similar to that of the Historical Center and Old City
population. However, the WTP of the Jabaquara population is assumed to be approximately half
of that for the Historical Center and Old City population, since it will be provided with only half
of the service, which is the supply of treated drinking water.
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WTP (Jabaquara) = WTP (Historical Center, and Old City)/2 = R$26/household-month
The WTP, for the Jabaquara population, is approximately R$26/household-month.
Willingness to Pay
The WTP is approximately R$29/household-month for the low-income population in Mangueira
and Ilha das Cobras, $51/household-month for the mid- to high-income population in Historical
Center and Old City, and R$26/household-month for the Jabaquara population, who will receive
only the treated drinking water.
The WTP varies widely between the low-income population and the mid- to high-income
population, and the difference is approximately R$22/household-month, almost 80% of the WTP
of the low-income population. The WTP of the low-income population is approximately
R$9/household-month lower than the break-even water and sewage tariff, and the WTP of the
mid- to high-income population is approximately R$13/household-month higher.
4.6. Water and Sewage Tariff
The water and sewage tariff must be designed to reflect the people’s WTP, which varies with
income distribution, because the WTP of the low-income population is below the minimum
water and sewage tariff required for full cost recovery. Examples of income-based tariffs
include “lifeline” tariffs, and lump-sum credits provided to qualifying low-income households.
Lifeline tariffs, which are reduced tariffs applicable to low-income consumers, provide the low-
income consumers with a predetermined amount of service to meet a minimum quality of life.
Lifeline tariffs or other income transfers to low-income households are motivated and justified
by a goal to achieve “fairness,” even though they are in conflict with “equity.” Tariffs are fair
when they are perceived to be just and equitable by consumers and the general public. Many
members of the public believe that it is fair to charge lower prices to low-income households,
even though equity precludes non-cost-related differences in tariff as well as any other arbitrary
distinctions among users (Boland, 1992).
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In this study, a separate tariff for water and sewage is designed for each income group based on
the study of WTP. For example, water and sewage tariff of R$1.40/m3, corresponding to R$29
/household-month, is charged for the low-income households in Mangueira and Ilha das Cobras;
R$2.40/m3, corresponding to R$51/household-month, is charged for the mid- to high-income
households in Historical Center and Old City; and R$1.20/m3, corresponding to R$26/household-
month, is charged to mid- to high-income households in Jabaquara. This design of water and
Table 4.8. Water and sewage tariff adjusted according to income distribution1
The above tariffs are substantially higher than the existing tariffs of approximately
R$3/household-month in Mangueira and Ilha das Cobras, and R$7/household-month in other
parts of the City. Sudden increase in water and sewage tariffs of this magnitude is likely to
“shock” the users, and thus appropriate interim tariffs must be designed for one or more steps to
phase in the final design tariff.
4.7. Benefits
The benefits associated with water and sanitation improvements are numerous and substantial,
although it is difficult to associate these benefits with monetary values for cost-benefit analysis.
Some of the benefits include:
(i) Disease reduction and improved human productivity;
(ii) Healthier environment, improved aesthetics, and associated increase in amenities,
economic values, and intrinsic values of the environment;
1 hh= household; mo=month
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(iii) Encouraged tourism, poverty alleviation, and general economic growth; and
(iv) UNESCO World Heritage Site candidacy, and associated distinction and merit.
4.8. Summary
Following improvements are proposed for the mitigation of the City’s current water and
sanitation-related problems:
(i) Gravity sewer system for the collection of wastewater;
(ii) Chemically enhanced primary treatment (CEPT) plant for the treatment of wastewater; and
(iii) Drinking water treatment plant for a better treatment of potable water.
The wastewater collection infrastructure and treatment plant are to be constructed concurrently in
three stages for the City of Paraty, excluding the Jabaquara area. The Historical Center is to be
developed in the first stage; Mangueira and Ilha das Cobras in the second stage; and the Old City
and rest of the City in the third stage. Each development stage is to last approximately 2 years,
and the completion of each stage is to initiate an immediate start of the subsequent stage.
The drinking water disinfection system is to be upgraded immediately, with a flow meter and an
automated chlorinator, and the drinking water intake points are to be fenced around the
perimeter, in order to protect the source waters. The drinking water treatment plant, with the
capacity for the entire City of Paraty including Jabaquara, is to be constructed in one stage,
immediately following the third stage of wastewater infrastructure development.
The total capital costs and O&M costs associated with the above improvements are as follows:
Total Capital Costs and O&M Costs for Water and Sanitation Improvement Projects Total WW Collection Infrastructure and Treatment Plant CC R$ 4 million Total WW Collection and Treatment Annual O&M Cost R$ 0.5 million/yr Total DW Treatment Plant CC R$ 1 million Total DW Treatment Annual O&M Cost R$ 0.4 million/yr
Table 4.9. Total capital cost and O&M cost for water and sanitation improvement projects
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The total annual cost is approximately R$1.2 million, with the capital cost amortized over a 30-
year project life at 10% annual interest rate. The minimum water and sewage tariff required for
full recovery of this annual cost is approximately R$1.80/m3 or R$38/household-month.
The willingness to pay (WTP) varies between different areas of the City according to household
income. WTP is approximately R$29/household-month for the low-income population in
Mangueira and Ilha das Cobras, $51/household-month for the mid- to high-income population in
Historical Center and Old City, and R$26/household-month for the Jabaquara population, who
will receive only the treated drinking water.
Designing a separate water and sewage tariff for each income group, based on the study of WTP,
water and sewage tariff is R$1.40/m3 for Mangueira and Ilha das Cobras population, R$2.40/m3
for Historical Center and Old City population, and R$1.20/m3 for Jabaquara population. Since
these tariffs can be seen as a substantial increase from the existing tariffs, appropriate interim
tariffs are to be designed and implemented in one or more steps to phase in the final design tariff.
Finally, the construction of wastewater collection infrastructure and treatment plant, and drinking
water treatment plant is expected to bring substantial benefits in public health, environmental
quality, and aesthetics in the city, and hence provide large economic gains.
78
CHAPTER 5 - PROPOSED POLICY
City of Paraty currently suffers from inadequate water and sanitation systems, the consequences
of which include: poor public health; polluted surface waters; damaged aesthetics; loss of
amenities; and depreciated commercial and intrinsic value of the environment. In addition, the
City’s objective of becoming a UNESCO World Heritage Site has been deferred due to the lack
of functioning sanitation system in the Historical Center.
Problems
The potable water supply system for the City of Paraty has a number of problems that must be
addressed, including: (i) shortage of water supply in the summer; (ii) ineffective disinfection;
(iii) inadequate protection of water sources; and (iv) substandard water quality.
Numerous water quality analyses revealed that the quality of City’s potable water is heavily
influenced by the quality of surface waters, from which it is derived, and often fails to comply
with international drinking water standards due to high turbidity after rainstorms, and bacterial
contamination. These analyses also indicated that the City’s present method of disinfection is
ineffective, and that filtration of drinking water before disinfection is necessary in order to
remove suspended particulate matter, and the harmful pathogens adsorbed on those particles,
from water.
Due to the lack of wastewater collection and treatment, the City of Paraty suffers from serious
environmental degradation and associated health consequences. The environmental degradation
in the City results from the direct discharge of untreated sewage into surrounding water bodies,
and from the tidal inflows that flood the streets with sewage and seawater mixture.
Four surface water bodies, Jabaquara Beach, Matheus River, Pereque River, and an open ditch of
sewer stream, were tested for water quality. According to the water quality analyses, Jabaquara
Beach was found to be unsafe for swimming, and Matheus River and Pereque River unsafe for
all aquatic sports, due to high fecal contamination. In addition, Sewer stream was found to have
the water quality of a diluted sewage.
79
The uncontrolled disposal of wastewater damages the aesthetics of the rivers, and reduces the
commercial value of the environment. The source of pollution must be controlled in order to
preserve the environment from further degradation, and therefore an appropriate treatment and
discharge of the City’s wastewater is critical.
Poor public health is a direct consequence of inadequate potable water quality and polluted
environment. Diarrhea, a widely studied indicator of water and sanitation-related diseases, was
found to be prevalent in both the urban and the rural areas of Paraty, especially in Mangueira and
Ilha das Cobras, the more densely populated, low-income areas within the City of Paraty.
It is assumed that a significant proportion of diarrhea cases is caused by waterborne pathogens,
although it is difficult to estimate the exact proportion that is caused by the consumption of
poorly disinfected drinking water, or by the contact with polluted surface waters. For the City of
Paraty, it is speculated that both the ineffectively disinfected drinking water, and the highly
polluted surface waters are the causes of diarrhea and other water and sanitation related diseases.
Improvements
Following improvements are proposed for the mitigation of the City’s current water and
sanitation-related problems identified above:
(i) Gravity sewer system for the collection of wastewater;
(ii) Chemically enhanced primary treatment (CEPT) plant for the treatment of wastewater; and
(iii) Drinking water treatment plant for a better treatment of potable water.
The wastewater collection infrastructure and treatment plant are to be constructed concurrently in
three stages for the City of Paraty, excluding the Jabaquara area. The Historical Center is to be
developed in the first stage; Mangueira and Ilha das Cobras in the second stage; and the Old City
and rest of the City in the third stage. Each development stage is to last approximately 2 years,
and the completion of each stage is to initiate an immediate start of the subsequent stage.
80
The drinking water disinfection system is to be upgraded immediately, with a flow meter and an
automated chlorinator, and the drinking water intake points are to be fenced around the
perimeter, in order to protect the source waters. The drinking water treatment plant, with the
capacity for the entire City of Paraty including Jabaquara, is to be constructed in one stage,
immediately following the third stage of wastewater infrastructure development.
In order to fully recover costs of water and sanitation improvements, annual revenue of R$1.2
million must be collected from water and sewage tariffs. The following water and sewage
tariffs, which are based on willingness to pay (WTP), are to be billed for each income group:
R$1.40/m3 for Mangueira and Ilha das Cobras population; R$2.40/m3 for Historical Center and
Old City population; and R$1.20/m3 for Jabaquara population. Since these tariffs can be seen as
a substantial increase from the existing tariffs, appropriate interim tariffs are to be designed and
implemented in one or more steps to phase in the final design tariff.
Finally, the construction of wastewater collection infrastructure and treatment plant, and drinking
water treatment plant is expected to bring numerous and substantial benefits to the City, which
include: improvements in public health, environmental quality, and aesthetics in the city, as well
as increases in productivity and economic value of the environment. It is also expected that
these water and sanitation improvements will encourage tourism and promote general economic
growth, providing large economic returns.
81
APPENDIX A – Water Quality Test Data
82
Water Quality Test Data for Drinking Water Samples from the City of Paraty
Chlorine
Sample # Location Detail Date Collection
Time Turbidity
(NTU) SS
(mg/L) pH Free Cl (mg/L)
Tot Cl (mg/L)
14 Caboclo 1/10/2003 5:40 PM 1.4 1 6.2 18 Caboclo At reservoir 1/13/2003 10:20 AM 2.9 3 6.9 23 Caboclo At reservoir 1/14/2003 10:00 AM 4.5 8 6.6 29 Caboclo At reservoir 1/16/2003 9:30 AM 2.7 3 6.6 37 Caboclo At reservoir 1/17/2003 12:00 PM 3.2 1 6.7 42 Caboclo At reservoir 1/17/2003 4:00 PM 3.1 3 6.4 46 Caboclo At reservoir 1/18/2003 12:45 PM 3.5 7 7.0 51 Caboclo At reservoir 1/20/2003 11:05 AM 1.8 2 6.8 56 Caboclo At reservoir 1/21/2003 12:00 PM 1.7 3 6.9 13 Pedra Branca 1/10/2003 5:00 PM 1.2 2 6.0 41 Pedra Branca 1/17/2003 3:45 PM 8.1 7 6.4 45 Pedra Branca 1/18/2003 12:05 PM 0.7 3 7.1 50 Pedra Branca 1/20/2003 10:50 AM 1.5 2 7.0 55 Pedra Branca 1/21/2003 11:30 AM 2.5 3 7.1 15 Reservoir After chlorination 1/10/2003 6:00 PM 3.2 3 6.2 24 Reservoir After chlorination 1/14/2003 10:05 AM 8.6 10 6.4 30 Reservoir After chlorination 1/16/2003 9:40 AM 6.9 6 6.4 0.15 38 Reservoir After chlorination 1/17/2003 12:10 PM 2.0 1 6.6 3.40 8.30 43 Reservoir After chlorination 1/17/2003 4:05 PM 4.0 4 6.5 47 Reservoir After chlorination 1/18/2003 12:50 PM 1.7 7 6.8 0.01 0.13 52 Reservoir After chlorination 1/20/2003 11:10 AM 1.4 3 7.0 0.58 0.2 57 Reservoir After chlorination 1/21/2003 12:00 PM 1.8 2 7.0 35 Tap Water 1/16/2003 4:40 PM 4.0 3 5.7 1.51 61 Tap Water 1/21/2003 2:00 PM 1.6 2 6.8 1.43 1.59 64 Tap Water 1/21/2003 5:30 PM 4.1 5 6.7 65 Tap Water 1/22/2003 10:00 AM 67.5 44 6.6 0.04 0.15 66 Tap Water 1/22/2003 10:10 AM 11.5 7 6.6 76 Tap Water 1/23/2003 5:10 PM 0.65 0.77
83
Water Quality Test Data for Drinking Water Samples from the City of Paraty (Cont’d)
Coliform Total Count
Fecal MPN
Fecal Count
Total MPN Weather
96 > 2424 50 188 sunny, 4 days after heavy rain cloudy, cool, 1 day after rain
96 > 2424 54 213 cloudy, rained the night before 88 794 38 127 sunny, partly cloudy, rained the night before 95 2424 28 87 really sunny, rained lightly night before 96 > 2424 69 339 started raining 96 > 2424 50 188 rained heavily the night before 94 1696 53 206 sunny, rained very lightly the night before 96 > 2424 29 90 very sunny, before rain 96 > 2424 3 8 sunny, 4 days after heavy rain 96 > 2424 65 298 started raining 96 > 2424 31 98 rained heavily the night before 96 > 2424 69 339 sunny, rained very lightly the night before 95 2424 14 39 very sunny, before rain 1 3 0 < 3 sunny, 4 days after heavy rain 4 11 0 < 3 cloudy, rained the night before 0 < 3 0 < 3 sunny, partly cloudy, rained the night before 0 < 3 0 < 3 really sunny, rained lightly night before 0 < 3 0 < 3 started raining 3 8 0 < 3 rained heavily the night before 95 2424 14 39 sunny, rained very lightly the night before 0 < 3 0 < 3 very sunny, before rain 0 < 3 0 < 3 sunny, partly cloudy, rained the night before 0 < 3 0 < 3 very sunny, before rain 0 < 3 0 < 3 immediately after storm 96 > 2424 75 418 sunny, before rain 71 362 0 < 3 sunny, before rain sunny, day after rain
84
Water Quality Test Data for Drinking Water Samples from Rural Communitites within Municipality of Paraty
Water Quality Test Data for Drinking Water Samples from Rural Communitites within Municipality of Paraty (Cont’d)
Coliform Total Count
Fecal MPN
Fecal Count
Total MPN Weather
74 403 1 3 really sunny, rained lightly night before 92 1174 0 < 3 sunny, rained very lightly the night before 96 > 2424 2 5 very sunny, before rain 96 > 2424 17 49 rained heavily 96 > 2424 11 30 rained heavily the night before 92 1174 4 11 sunny, rained very lightly the night before 81 534 4 11 sunny, day after rain 96 > 2424 11 30 rained heavily 96 > 2424 87 740 rained heavily 96 > 2424 16 46 rained heavily 96 > 2424 8 22 rained heavily 90 938 23 69 rained heavily 93 1370 2 5 sunny, day after rain
86
Results of Water Quality Analysis performed by the Municipality of Paraty from October 2001 to March 2002 For Drinking Water Sampled from Various Communities within the Municality of Paraty
Location Date (dd/ mm/yy) Time Treatment
Turbidity/ Suspended Solids (ss) Color Odor
Total Coliform
Fecal Coliform Conclusion
Barra Grande 17/10/01 15:30 None high ss none none present present not satisfactory Barra Grande 23/01/02 15:55 None clear none none present present not satisfactory
Paraty City 17/10/01 13:30 Chlorination clear none none absent absent satisfactory Paraty City 06/02/02 18:50 Chlorination clear none none absent absent satisfactory Paraty City 19/12/01 18:35 Chlorination clear none none absent absent satisfactory Paraty City 19/12/01 18:50 Chlorination clear none none absent absent satisfactory Paraty City 23/01/02 16:43 Chlorination clear none none present present not satisfactory Paraty City 06/02/02 18:25 Chlorination clear none none absent absent satisfactory Paraty City 19/12/01 18:25 Chlorination high ss none none present absent not satisfactory Paraty City 17/10/01 15:10 Chlorination clear none none absent absent satisfactory Paraty City 06/03/02 17:45 Chlorination clear none none present absent not satisfactory Paraty City 17/10/01 15:00 Chlorination clear none none absent absent satisfactory Paraty City 23/01/02 15:35 Chlorination clear none none present present not satisfactory Paraty City 06/03/02 17:10 Chlorination clear none none absent absent satisfactory Paraty City 23/01/02 17:05 Chlorination clear none none absent absent satisfactory Paraty City 06/02/02 18:40 Chlorination clear none none absent absent satisfactory Paraty City 06/03/02 14:35 Chlorination clear none none absent absent satisfactory Paraty City 17/10/01 14:35 Chlorination clear none none absent absent satisfactory Paraty City 23/01/02 16:55 Chlorination clear none none absent absent satisfactory
Pastiba 19/12/01 18:00 None high ss none none absent absent not satisfactory Patrimonio 06/02/02 16:34 None clear none none present present not satisfactory Patrimonio 19/12/01 15:40 None clear none none present present not satisfactory
Pedras Azuis 06/02/02 16:12 None clear none none present present not satisfactory Pedras Azuis 19/12/01 16:40 None cloudy yellow none present present not satisfactory Ponte Branca 06/02/02 17:55 Chlorination clear none none absent absent satisfactory Ponte Branca 19/12/01 17:40 Chlorination high ss none none absent absent not satisfactory
Taquari 06/03/02 15:45 None clear none none present absent not satisfactory Taquari 18/10/01 7:00 None clear none none present present not satisfactory Tarituba 06/03/02 16:00 None clear none none present absent not satisfactory Tarituba 18/10/01 7:40 None clear none none present present not satisfactory Trindade 06/02/02 16:55 None clear none none present present not satisfactory Trindade 19/12/01 15:20 None high ss none none present present not satisfactory
87
Water Quality Test Data for Surface Water Samples from the City of Paraty
Sample # Location Date
Collection Time
Turbidity (NTU)
SS (mg/L) pH COD (mg/L)
1 Jabaquara Beach 1/8/2003 10:20 AM 8.6 6 6.8 1.4E+03 5 Jabaquara Beach 1/8/2003 5:20 PM 34.5 39 7.9 > 1.7E+03 10 Jabaquara Beach 1/9/2003 4:15 PM 25.5 23 5.8 1.1E+03 11 Jabaquara Beach 1/9/2003 4:20 PM 43.3 42 6.1 > 1.7E+03 16 Jabaquara Beach 1/11/2003 2:00 PM 42.4 32 6.8 7.3E+01 19 Jabaquara Beach 1/13/2003 10:40 AM 9.7 11 6.6 > 1.7E+03 25 Jabaquara Beach 1/14/2003 10:15 AM 6.8 10 7.7 1.2E+02 31 Jabaquara Beach 1/16/2003 10:00 AM 21.8 20 6.8 1.1E+02 40 Jabaquara Beach 1/17/2003 3:20 PM 31.4 31 7.7 2.3E+02 53 a Jabaquara Beach 1/20/2003 12:20 PM 19.2 18 6.7 53 b Jabaquara Beach 60 a Jabaquara Beach 1/21/2003 12:05 PM 17.3 16 6.8 60 b Jabaquara Beach 3 Matheus River 1/8/2003 3:40 PM 6.2 9 6.5 8.1E+02 8 a Matheus River 1/9/2003 10:50 AM 8.2 14 6.6 3.1E+02 8 b Matheus River 21 Matheus River 1/13/2003 11:25 AM 6.5 6 6.8 7.9E+01 27 Matheus River 1/14/2003 11:00 AM 17.4 21 7.4 3.2E+01 33 Matheus River 1/16/2003 10:30 AM 30.4 29 7.0 8.5E+01 58 a Matheus River 1/21/2003 12:20 PM 10.2 11 6.8 8.6E+01 58 b Matheus River 62 Matheus River 1/21/2003 3:30 PM 13.4 14 6.6 1.0E+01 2 Pereque River 1/8/2003 10:40 AM 4.9 3 6.4 5.7E+01 6 Pereque River 1/8/2003 5:45 PM 8.8 18 5.9 1.2E+01 12 a Pereque River 1/9/2003 4:50 PM 10.8 9 6.6 3.3E+01 12 b Pereque River 17 Pereque River 1/11/2003 2:20 PM 45.5 38 7.3 2.6E+01 20 Pereque River 1/13/2003 10:50 AM 7.4 7 7.4 1.7E+01 26 Pereque River 1/14/2003 10:35 AM 16.0 18 8.0 1.4E+01 32 Pereque River 1/16/2003 10:15 AM 33.8 30 7.4 2.1E+01 59 a Pereque River 1/21/2003 12:45 PM 12.0 12 7.0 1.6E+01 59 b Pereque River 63 Pereque River 1/21/2003 3:50 PM 20.3 20 6.5 2.3E+02 9 a Sewer Stream 1/9/2003 11:00 AM 28.5 31 6.5 1.1E+03 9 b Sewer Stream 22 Sewer Stream 1/13/2003 11:30 AM 89.6 102 6.8 2.8E+02 28 Sewer Stream 1/14/2003 11:15 AM 48.2 63 7.1 3.7E+02 34 Sewer Stream 1/16/2003 10:40 AM 34.4 48 6.8 1.1E+02 Raw Sewage 1/23/2003 128.0 117 6.8 4.1E+02
88
Water Quality Test Data for Surface Water Samples from the City of Paraty (Continued)
Coliform
Dilution by Total Count Total MPN Fecal Count Fecal MPN Weather
66 3.1E+02 45 1.6E+02 sunny, 2 days after heavy rain 7 1.9E+01 9 2.5E+01 sunny, 2 days after heavy rain
10^(-2) 11 3.0E+03 0 < 3.0E+02 sunny, 3 days after heavy rain 10^(-2) 2 5.0E+02 0 < 3.0E+02 sunny, 3 days after heavy rain 10^(-1) 66 3.1E+03 6 1.6E+02 started raining
cloudy, cool, 1 day after rain 10^(-1) 32 1.0E+03 0 < 3.0E+01 cloudy, rained the night before
96 > 2.4E+03 82 5.6E+02 sunny, partly cloudy, rained the night before 0 < 3.0E+00 1 3.0E+00 started raining 96 > 2.4E+03 60 2.6E+02 sunny, rained very lightly the night before
10^(-1) 96 > 2.4E+04 25 7.6E+02 sunny, rained very lightly the night before 16 4.6E+01 3 8.0E+00 very sunny, before rain
10^(-1) 96 > 2.4E+03 7 1.9E+01 very sunny, before rain 79 4.9E+02 96 > 2.4E+03 sunny, 2 days after heavy rain
10^(-1) 96 > 2.4E+04 96 > 2.4E+04 sunny, 3 days after heavy rain 10^(-2) 96 > 2.4E+05 79 4.9E+04 sunny, 3 days after heavy rain
cloudy, cool, 1 day after rain 10^(-3) 35 1.1E+05 10 2.8E+04 cloudy, rained the night before 10^(-3) 9 2.5E+04 0 < 3.0E+03 sunny, partly cloudy, rained the night before 10^(-2) 96 > 2.4E+05 58 2.4E+04 very sunny, before rain 10^(-3) 78 4.7E+05 21 6.2E+04 very sunny, before rain 10^(-2) 96 > 2.4E+05 81 5.3E+04 immediately after storm
96 > 2.4E+03 96 > 2.4E+03 sunny, 2 days after heavy rain 96 > 2.4E+03 96 > 2.4E+03 sunny, 2 days after heavy rain
10^(-3) 38 1.3E+05 11 3.0E+04 sunny, 3 days after heavy rain 10^(-4) 9 2.5E+05 1 3.0E+04 sunny, 3 days after heavy rain 10^(-3) 83 5.9E+05 7 1.9E+04 after rain, rapid flow
cloudy, cool, 1 day after rain 10^(-3) 29 9.0E+04 1 3.0E+03 cloudy, rained the night before 10^(-3) 8 2.2E+04 0 < 3.0E+03 sunny, partly cloudy, rained the night before 10^(-2) 91 1.0E+05 45 1.6E+04 very sunny, before rain 10^(-3) 50 1.9E+05 1 3.0E+03 very sunny, before rain 10^(-2) 96 > 2.4E+05 78 4.7E+04 immediately after storm 10^(-4) 84 6.2E+06 45 1.6E+06 sunny, 3 days after heavy rain 10^(-5) 32 1.0E+07 6 1.6E+06 sunny, 3 days after heavy rain
cloudy, cool, 1 day after rain 10^(-5) 44 1.6E+07 6 1.6E+06 cloudy, rained the night before 10^(-5) 50 1.9E+07 9 2.5E+06 sunny, partly cloudy, rained the night before
3.3E+06 4.6E+05
89
APPENDIX B – Diarrhea Incidence Data
90
Number of Diarrhea Cases in the Municipality of Paraty From September 1 to December 28, 2002 In the Low-Income Urban Areas
Week No. Start Date End Date U.Saude Location Description No. Cases 36 9/1/2002 9/7/2002 HMSPA Ilha das Cobras Urban 2 37 9/8/2002 9/14/2002 HMPA Ilha das Cobras Urban 1 39 9/22/2002 9/28/2002 ESF Ilha das Cobras Urban 8 39 9/22/2002 9/28/2002 HMSPA Ilha das Cobras Urban 3 40 9/29/2002 10/5/2002 HMSPA Ilha das Cobras Urban 5 41 10/6/2002 10/12/2002 HMSPA Ilha das Cobras Urban 1 42 10/13/2002 10/19/2002 HMSPA Ilha das Cobras Urban 1 43 10/20/2002 10/26/2002 Ilha das Cobras Urban 11 43 10/20/2002 10/26/2002 HMSPA Ilha das Cobras Urban 1 45 11/3/2002 11/9/2002 HMSPA/PSF Ilha das Cobras Urban 10 46 11/10/2002 11/16/2002 Hospital/PSF Ilha das Cobras Urban 2 48 11/24/2002 11/30/2002 HMSPA/ESF Ilha das Cobras Urban 7 49 12/1/2002 12/7/2002 HMSPA/ESF Ilha das Cobras Urban 7 50 12/8/2002 12/14/2002 HMSPA/ESF Ilha das Cobras Urban 3 51 12/15/2002 12/21/2002 HMSPA/ESF Ilha das Cobras Urban 1 52 12/22/2002 12/28/2002 HMSPA/ESF Ilha das Cobras Urban 6 36 9/1/2002 9/7/2002 HMSPA Mangueira Urban 2 37 9/8/2002 9/14/2002 HMPA Mangueira Urban 2 37 9/8/2002 9/14/2002 PSF Mangueira Urban 1 39 9/22/2002 9/28/2002 ESF Mangueira Urban 1 39 9/22/2002 9/28/2002 HMSPA Mangueira Urban 1 40 9/29/2002 10/5/2002 HMSPA Mangueira Urban 6 41 10/6/2002 10/12/2002 HMSPA Mangueira Urban 2 42 10/13/2002 10/19/2002 HMSPA Mangueira Urban 5 43 10/20/2002 10/26/2002 HMSPA Mangueira Urban 5 44 10/27/2002 11/2/2002 PSF Mangueira Urban 2 44 10/27/2002 11/2/2002 HMSPA Mangueira Urban 11 45 11/3/2002 11/9/2002 HMSPA/PSF Mangueira Urban 4 46 11/10/2002 11/16/2002 Hospital/PSF Mangueira Urban 4 47 11/17/2002 11/23/2002 HMSPA/PSF Mangueira Urban 4 48 11/24/2002 11/30/2002 HMSPA/ESF Mangueira Urban 4 49 12/1/2002 12/7/2002 HMSPA/ESF Mangueira Urban 6 50 12/8/2002 12/14/2002 HMSPA/ESF Mangueira Urban 3 51 12/15/2002 12/21/2002 HMSPA/ESF Mangueira Urban 2 52 12/22/2002 12/28/2002 HMSPA/ESF Mangueira Urban 3
Total (Urban, Poor)= 137 Percent (Urban, Poor)= 60% Number of Diarrhea Cases in the Municipality of Paraty From September 1 to December 28, 2002 In the Mid-to-High-Income Urban Areas
Week No. Start Date End Date U.Saude Location Description No. Cases 38 9/15/2002 9/21/2002 HSPA Cabore Urban 1 40 9/29/2002 10/5/2002 HMSPA Cabore Urban 1 45 11/3/2002 11/9/2002 HMSPA/PSF Cabore Urban 1 50 12/8/2002 12/14/2002 HMSPA/ESF Cabore Urban 2 38 9/15/2002 9/21/2002 HSPA Centro Urban 1 40 9/29/2002 10/5/2002 HMSPA Centro Urban 2 42 10/13/2002 10/19/2002 HMSPA Centro Urban 1 47 11/17/2002 11/23/2002 HMSPA/PSF Centro Urban 1 48 11/24/2002 11/30/2002 HMSPA/ESF Centro Urban 1 49 12/1/2002 12/7/2002 HMSPA/ESF Centro Urban 1 38 9/15/2002 9/21/2002 HSPA Chacara Urban 1
91
Number of Diarrhea Cases in the Municipality of Paraty From September 1 to December 28, 2002 In the Mid-to-High-Income Urban Areas (Continued)
Number of Diarrhea Cases in the Municipality of Paraty From September 1 to December 28, 2002 In the Rural Areas (Continued) Week No. Start Date End Date U.Saude Location Description No. Cases
Total (Rural) = 204 Percent (Rural) = 46% Number of Diarrhea Cases in the Municipality of Paraty From September 1 to December 28, 2002 From outside population Week No. Start Date End Date U.Saude Location Description No. Cases
40 9/29/2002 10/5/2002 HMSPA Externo Other 1 45 11/3/2002 11/9/2002 HMSPA/PSF Externo Other 1 46 11/10/2002 11/16/2002 Hospital/PSF Externo Other 1 48 11/24/2002 11/30/2002 HMSPA/ESF Outro Municipio Other 1 51 12/15/2002 12/21/2002 HMSPA/ESF Outro Municipio Other 1 52 12/22/2002 12/28/2002 HMSPA/ESF Outro Municipio Other 5 43 10/20/2002 10/26/2002 HMSPA Sao Paulo Other 1
Total (Other) = 11 Percent (Other) = 2% Total = 443 Number of Diarrhea Cases in the Municipality of Paraty From September 1 to December 28, 2002 Summary by Location No. Cases Percent Urban = 228 51% Ilha das Cobras, Mangueira = 137 60% Other = 91 40% Rural = 204 46% Other = 11 2% Total = 443 100%
95
Morbidity of Diarrhea Cases in the Municipality of Paraty From September 1 to December 28, 2002 Summary by Diagnosis (Type of Treatment Plan)
Total Number of Cases (by Plan Type) = 254 31 41 117 443Percent Number of Cases (by Plan Type) = 57% 7% 9% 26% 100% Plan A: No sign of dehydration Plan B: Two or more signs of dehydration Plan C: Two or more signs, including one that shows serious dehydration
96
APPENDIX C – Financial Data
97
Monthly Water and Sewage Tariff Invoiced and Collected by the City of Paraty from January 2000 to November 2002 Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2000 R$ 49,000 R$ 39,000 R$ 57,000 R$ 46,000 R$ 32,000 R$ 31,000 R$ 46,000 R$ 38,000 R$ 23,000 R$ 41,000 R$ 40,000 R$ 63,0002001 R$ 65,000 R$ 21,000 R$ 74,000 R$ 66,000 R$ 37,000 R$ 34,000 R$ 43,000 R$ 45,000 R$ 38,000 R$ 33,000 R$ 39,000 R$ 48,0002002 R$ 30,000 R$ 29,000 R$ 42,000 R$ 37,000 R$ 48,000 R$ 34,000 R$ 44,000 R$ 35,000 R$ 45,000 R$ 35,000 R$ 35,000
Project Life 30 years Interest Rate 5% /year 10% /year Population 15,000 capita Average Water Tariff (Reference) 0.73 R$/m^3 15.37 R$/household-month Average Sewage Tariff (Reference) 0.87 R$/m^4 18.32 R$/household-month Tariff Collected/Billed 70% DESIGN PARAMETERS: POPULATION
Area Average Peak (Summer) Jabaquara 1,500 capita 3 4500 capita Historical Center 3,000 capita 3 9000 capita Mangueira 4,500 capita 1 4500 capita Ilha das Cobras 3,000 capita 1 3000 capita Old City 3,000 capita 3 9000 capita Total Urban Population 15,000 capita 30,000 capita Population Growth Rate 0.8% /year DESIGN PARAMETERS: OTHER
CALCULATION OF COSTS FOR WW TREATMENT AND INFRASTRUCTURE DESIGN PARAMETERS: POPULATION
Area Average Peak (Summer) Jabaquara 1,500 capita 3 4,500 capita Historical Center 3,000 capita 3 9,000 capita Mangueira 4,500 capita 1 4,500 capita Ilha das Cobras 3,000 capita 1 3,000 capita Old City 3,000 capita 3 9,000 capita Total Urban Population 15,000 capita 0 30,000 capita Population Growth Rate 0.8% /year DESIGN PARAMETERS: OTHER
Exchange Rate Brazilian to US 3 R$/US$ Buying Power in US to in Brazil Ratio 0.3 US Cost to Brazilian Cost Conversion Factor 1.0 R$/US$ WW DEVELOPMENT STAGES
Development Stage 1: Historical Center Design Population for Dev. Stage 1 9,000 capita Development Stage 2: Mangueira + Ilha das Cobras Design Population for Dev. Stage 2 7,500 capita Development Stage 3: Old City Design Population for Dev. Stage 3 9,000 capita
102
CALCULATION OF COSTS FOR WW TREATMENT AND INFRASTRUCTURE Development Stage 1: Historical Center DESIGN PARAMETERS: Stage 1
Design Population 9,000 capita Design Flow for WW Treatment CC 3,240 m^3/day Design Flow for WW Infrastructure CC 1,620 m^3/day Design Flow for WW O&M 1,620 m^3/day COSTS: Stage 1
CEPT CC (2x) 1,810 R$1000 for flow of 14,000 m^3/d 0.23 419 R$1000 for flow of 3,240 m^3/dDisinfection CC (2x) 1,810 R$1000 for flow of 14,000 m^3/d 0.23 419 R$1000 for flow of 3,240 m^3/dSludge treatment CC (2x) 320 R$1000 for flow of 14,000 m^3/d 0.23 74 R$1000 for flow of 3,240 m^3/dWW Treatment CC 912 R$1000 CEPT O&M 10 R$1000/yr for flow of 14,000 m^3/d 0.12 1.2 R$1000/yr for flow of 1,620 m^3/dDisinfection of effluent O&M 6 US$1000/yr for flow of 1,000 m^3/d 1.62 10 R$1000/yr for flow of 1,620 m^3/dSludge treatment and disposal O&M 12 R$1000/yr for flow of 14,000 m^3/d 0.12 1.4 R$1000/yr for flow of 1,620 m^3/dWW Treatment O&M 13 R$1000/yr Piping, pump stations, manholes, and other 1,000 US$1000 for flow of 1,620 m^3/d 1.00 1,026 R$1000/yr for flow of 1,620 m^3/dWW Infrastructure CC 1,026 R$1000 Piping, pump stations, manholes, and other 150 US$1000/yr for flow of 1,620 m^3/d 1.00 154 R$1000/yr for flow of 1,620 m^3/dWW Infrastructure O&M 154 R$1000/yr
103
CALCULATION OF COSTS FOR WW TREATMENT AND INFRASTRUCTURE Development Stage 2: Mangueira and Ilha das Cobras
DESIGN PARAMETERS: Stage 2
Additional Population 7,500 capita Design Flow for WW Treatment & Infrast. CC 1,350 m^3/day Design Flow for WW O&M 2,970 m^3/day
COSTS: Stage 2
CEPT CC 1,810 R$1000 for flow of 14,000 m^3/d 0.10 175 R$1000 for flow of 1,350 m^3/dDisinfection CC 1,810 R$1000 for flow of 14,000 m^3/d 0.10 175 R$1000 for flow of 1,350 m^3/dSludge treatment CC 320 R$1000 for flow of 14,000 m^3/d 0.10 31 R$1000 for flow of 1,350 m^3/dWW Treatment CC 380 R$1000 CEPT O&M 10 R$1000/yr for flow of 14,000 m^3/d 0.21 2.1 R$1000/yr for flow of 2,970 m^3/dDisinfection of effluent O&M 6 US$1000/yr for flow of 1,000 m^3/d 2.97 18 R$1000/yr for flow of 2,970 m^3/dSludge treatment and disposal O&M 12 R$1000/yr for flow of 14,000 m^3/d 0.21 2.5 R$1000/yr for flow of 2,970 m^3/dWW Treatment O&M 23 R$1000/yr Piping, manholes, and other 900 US$1000 for flow of 1,620 m^3/d 0.83 770 R$1000/yr for flow of 1,350 m^3/dWW Infrastructure CC 770 R$1000 Piping, pump stations, manholes, and other 150 US$1000/yr for flow of 1,620 m^3/d 1.83 282 R$1000/yr for flow of 2,970 m^3/dWW Infrastructure O&M 282 R$1000/yr
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CALCULATION OF COSTS FOR WW TREATMENT AND INFRASTRUCTURE Development Stage 3: Old City and other areas
DESIGN PARAMETERS: Stage 3
Additional Population 9,000 capita Design Flow for WW Infrastructure CC 1,620 m^3/day Design Flow for WW O&M 4,590 m^3/day
COSTS: Stage 3
WW Treatment CC 0 R$1000 CEPT O&M 10 R$1000/yr for flow of 14,000 m^3/d 0.33 3.3 R$1000/yr for flow of 4,590 m^3/dDisinfection of effluent O&M 6 US$1000/yr for flow of 1,000 m^3/d 4.59 28.3 R$1000/yr for flow of 4,590 m^3/dSludge treatment and disposal O&M 12 R$1000/yr for flow of 14,000 m^3/d 0.33 3.9 R$1000/yr for flow of 4,590 m^3/dWW Treatment O&M 35 R$1000/yr Piping,manholes, and other 900 US$1000 for flow of 1,620 m^3/d 1.00 924 R$1000/yr for flow of 1,620 m^3/dWW Infrastructure CC 924 R$1000 Piping, pump stations, manholes, and other 150 US$1000/yr for flow of 1,620 m^3/d 2.83 436 R$1000/yr for flow of 4,590 m^3/dWW Infrastructure O&M 436 R$1000/yr
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CALCULATION OF COSTS FOR DW TREATMENT AND INFRASTRUCTURE With Development
DESIGN PARAMETERS: With Development
Design Population 30,000 capita Design Flow for WW CC 5,400 m^3/day Design Flow for WW O&M 5,400 m^3/day
COSTS: With Development
Conventional treatment and Chlorine disinfection 1,300 US$1000 for flow of 6,813 m^3/d 0.79 1,057 R$1000 for flow of 5,400 m^3/dDW Treatment CC 1,057 R$1000 Conventional treatment and Chlorine disinfection 486 US$1000/yr for flow of 6,813 m^3/d 0.79 395 R$1000/yr for flow of 5,400 m^3/dDW Treatment O&M 395 R$1000/yr DW Infrastructure CC Neglected due to lack of information 0 R$1000 DW Infrastructure O&M Neglected due to lack of information 0 R$1000/yr
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COSTS
WW Treatment CC (Stage 1) 912 R$1000 WW Treatment O&M (Stage 1) 13 R$1000/year WW Infrastructure CC (Stage 1) 1,026 R$1000 WW Infrastructure O&M (Stage 1) 154 R$1000/year WW Treatment CC (Stage 2) 380 R$1000 WW Treatment O&M (Stage 2) 23 R$1000/year WW Infrastructure CC (Stage 2) 770 R$1000 WW Infrastructure O&M (Stage 2) 282 R$1000/year WW Treatment CC (Stage 3) 0 R$1000 WW Treatment O&M (Stage 3) 35 R$1000/year WW Infrastructure CC (Stage 3) 924 R$1000 WW Infrastructure O&M (Stage 3) 436 R$1000/year DW Treatment CC (w/o development) 0 R$1000 DW Treatment O&M (w/o development) 0 R$1000/year Neglected due to lack of information DW Infrastructure CC (w/o development) 0 R$1000 DW Infrastructure O&M (w/o development) 0 R$1000/year Neglected due to lack of information DW Treatment CC (w/ development) 1,057 R$1000 DW Treatment O&M (w/ development) 395 R$1000/year DW Infrastructure CC (w/ development) 0 R$1000 Neglected due to lack of information DW Infrastructure O&M (w/ development) 0 R$1000/year Neglected due to lack of information
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COST ANALYSIS CALCULATION OF WATER AND SEWAGE TARIFF REQUIRED WHEN BENEFIT:COST RATIO = 1.
Scenario Equivalent Uniform
Annual Cost (R$1000)
Equivalent Uniform Annual Benefit
(R$1000) Break-Even Water and Sewage Tariff (R$/m^3)
NPV of Annual Net Benefit
NPV of Annual Cash Flow (R$1000)
IRR of Annual Cash Flow
I = 5% I = 10% I = 5% I = 10% I = 5% I = 10% I = 5% I = 10% I = 5% I = 10% I = 5% I = 10% 1 1,086 1,226 1,086 1,226 1.57 1.78 0 0 95 222 5% 11%2 976 1,058 976 1,058 1.42 1.53 0 0 6 157 5% 11%3 955 1,030 955 1,030 1.38 1.49 0 0 -7 149 5% 11%4 934 1,004 934 1,004 1.35 1.46 0 0 -20 142 5% 11%
WATER AND SEWAGE TARIFF (R$/m^3)
Scenario I = 5% I = 10%
1 2 1.42 1.53 3 1.38 1.49 4 1.35 1.46
ANALYSIS OF WATER AND SEWAGE TARIFF = R$ 1.60/ m^3
Scenario Equivalent Uniform
Annual Cost (R$1000)
Equivalent Uniform Annual Benefit
(R$1000) Benefit:Cost Ratio NPV of Annual Net
Benefit NPV of Annual Cash
Flow (R$1000) IRR of Annual Cash
Flow I = 5% I = 10% I = 5% I = 10% I = 5% I = 10% I = 5% I = 10% I = 5% I = 10% I = 5% I = 10%
Annual Revenue Req'd 1,086 R$1000 Total Amount to Bill 1551 R$1000 Water & Sewage Tariff 1.57 R$/m^3 33 R$/household-month Water& Sewage Tariff 1.60 R$/m^3 34 R$/household-month (Previously set by CEDAE) NPV of Net Benefit 0 R$1000 NPV of Net Cash Flow 95 R$1000 Benefit:Cost Ratio 1
Total Cost Revenue NPV Net Benefit Total Cost = CC+O&M
Annual Revenue Req'd 1,226 R$1000 Total Amount to Bill 1752 R$1000 Water & Sewage Tariff 1.78 R$/m^3 37 R$/household-month Water& Sewage Tariff 1.60 R$/m^3 34 R$/household-month (Previously set by CEDAE) NPV of Net Benefit 0 R$1000 NPV of Net Cash Flow 222 R$1000 Benefit:Cost Ratio 1
Total Cost Revenue NPV Net Benefit Total Cost = CC+O&M
Annual Revenue Req'd 976 R$1000 Total Amount to Bill 1395 R$1000 Water & Sewage Tariff 1.42 R$/m^3 30 R$/household-month Water& Sewage Tariff 1.60 R$/m^3 34 R$/household-month (Previously set by CEDAE) NPV of Net Benefit 0 R$1000 NPV of Net Cash Flow 6 R$1000 Benefit:Cost Ratio 1
Total Cost Revenue NPV Net Benefit Total Cost = CC+O&M
Annual Revenue Req'd 1,058 R$1000 Total Amount to Bill 1511 R$1000 Water & Sewage Tariff 1.53 R$/m^3 32 R$/household-month Water& Sewage Tariff 1.60 R$/m^3 34 R$/household-month (Previously set by CEDAE) NPV of Net Benefit 0 R$1000 NPV of Net Cash Flow 157 R$1000 Benefit:Cost Ratio 1
Total Cost Revenue NPV Net Benefit Total Cost = CC+O&M
Annual Revenue Req'd 955 R$1000 Total Amount to Bill 1,364 R$1000 Break-even Tariff 1.38 R$/m^3 29 R$/household-month Water& Sewage Tariff 1.60 R$/m^3 34 R$/household-month (Previously set by CEDAE) NPV of Net Benefit 0 R$1000 NPV of Net Cash Flow -7 R$1000 Benefit:Cost Ratio 1
Total Cost Revenue NPV Net Benefit Total Cost = CC+O&M
Annual Revenue Req'd 1,030 R$1000 Total Amount to Bill 1,471 R$1000 Break-even Tariff 1.49 R$/m^3 31 R$/household-month Water& Sewage Tariff 1.60 R$/m^3 34 R$/household-month (Previously set by CEDAE) NPV of Net Benefit 0 R$1000 NPV of Net Cash Flow 149 R$1000 Benefit:Cost Ratio 1
Total Cost Revenue NPV Net Benefit Total Cost = CC+O&M
Annual Revenue Req'd 934 R$1000 Total Amount to Bill 1,335 R$1000 Break-even Tariff 1.35 R$/m^3 29 R$/household-month Water& Sewage Tariff 1.60 R$/m^3 34 R$/household-month (Previously set by CEDAE) NPV of Net Benefit 0 R$1000 NPV of Net Cash Flow -20 R$1000 Benefit:Cost Ratio 1
Total Cost Revenue NPV Net Benefit Total Cost = CC+O&M
Annual Revenue Req'd 1,004 R$1000 Total Amount to Bill 1,434 R$1000 Break-even Tariff 1.46 R$/m^3 31 R$/household-month Water& Sewage Tariff 1.60 R$/m^3 34 R$/household-month (Previously set by CEDAE) NPV of Net Benefit 0 R$1000 NPV of Net Cash Flow 142 R$1000 Benefit:Cost Ratio 1
Total Cost Revenue NPV Net Benefit Total Cost = CC+O&M
